2. Is a UK Ton larger than a US Ton?

Yes, a UK long ton (2,240 lb / 1,016 kg) is 12% larger than a US short ton (2,000 lb / 907 kg) —specifically, 240 pounds heavier . This difference arose because the UK retained the traditional 112-pound Imperial hundredweight (20 cwt = 2,240 lb), while the US adopted a simplified 100-pound hundredweight (20 cwt = 2,000 lb) in the 19th century. The 12% difference is significant in large-scale commerce: 10,000 US short tons = 8,929 UK long tons (a shortfall of 1,071 long tons). This discrepancy caused confusion in transatlantic trade, requiring contracts to specify "long tons" or "short tons" explicitly. The metric tonne (1,000 kg) was partly adopted internationally to eliminate this Anglo-American ambiguity, being nearly equal to the long ton (1.6% lighter) but defined in the universal decimal system.

3. How does the UK Ton compare to the metric ton?

A UK long ton (1,016.047 kg) is 1.6% heavier than a metric tonne (1,000 kg) —specifically, ~16 kg or ~35 pounds heavier . This near-equivalence made conversion relatively straightforward during metrication: 1 long ton ≈ 1.016 tonnes, and 1 tonne ≈ 0.984 long tons. For rough estimates, many treated them as approximately equal, but precision trade required exact conversion (error of 1.6% matters for large shipments). Example: 100,000 long tons = 101,605 metric tonnes (1,605-tonne difference). The metric tonne's advantage: exact decimal definition (1,000 kg) integrates seamlessly with SI units, whereas the long ton (2,240 lbs, odd historical number) requires complex conversions. Despite metrication, some UK contexts preserve long tons: Royal Navy still reports ship displacement in long tons alongside metric figures, maintaining centuries of naval tradition.

4. Why did Britain use 2,240 pounds instead of a round number?

The 2,240-pound definition arose organically from medieval commerce, not rational design. It derives from the Imperial hundredweight system : 1 cwt = 8 stones = 8 × 14 lbs = 112 pounds . Twenty hundredweight = 20 × 112 = 2,240 pounds . This system was based on stones (14 lbs, traditional for weighing people and goods) rather than decimal convenience. Additionally, the "tun" (wine cask) traditionally weighed ~2,240 lbs when full, reinforcing this standard. When the Weights and Measures Act of 1824 standardized British units, lawmakers codified existing practice rather than inventing new decimal-friendly numbers. Result: An Imperial system built on 14s, 16s, 112s, and 2,240s—functional but mathematically awkward compared to the metric system's base-10 simplicity. This complexity was a major driver of global metrication in the 20th century, as decimal systems (1,000 kg tonne) are far easier for calculation and international trade.

5. Do modern British ships still use long tons?

Yes, but with caveats. The Royal Navy still officially reports warship displacement in long tons alongside metric tonnes, preserving centuries of naval tradition. Example: HMS Queen Elizabeth (2017) is listed as 65,000 long tons (~66,000 tonnes) displacement. However, merchant shipping has almost entirely switched to metric tonnes following international maritime conventions and UK metrication (1965-1990s). Modern cargo ships, tankers, and container vessels specify capacity in metric tonnes (deadweight tonnage, cargo capacity). Engineering calculations, fuel consumption, and port documentation now use metric. The Royal Navy's continued use of long tons is primarily ceremonial and historical —engineers work in metric internally, but public-facing documents honor tradition. Most Commonwealth navies (Australia, Canada, New Zealand) similarly list both units. Prediction: As older naval officers retire, long tons may eventually disappear even from Royal Navy specifications, becoming purely a historical footnote.

6. When did the UK stop using long tons officially?

The UK's transition was gradual, not instantaneous : 1965 : Government announced metrication program. 1970s-1980s : Industries progressively adopted metric units. 1995 : Metrication of trade largely complete; the Weights and Measures Act 1985 required most goods sold by weight to use metric. However, "official" cessation is complex : Some sectors retain long tons (e.g., Royal Navy). Road signs still use miles (not metric). Pubs serve pints (568 ml, not 500 ml metric). Thus, metrication was incomplete: "soft" metrication allowed dual units. By the late 1990s-2000s , most commerce, manufacturing, and shipping had switched to metric tonnes, making long tons rare outside specific legacy contexts. Practically, long tons ceased being the default standard around 1990-2000, but they never disappeared entirely. Older Britons still think in stones/pounds for body weight, and tonnes sometimes mentally convert to long tons. Full cultural shift may take another generation.

7. What's the difference between a long ton and a freight ton?

Long ton and freight ton (also called measurement ton ) measure different things : Long ton : Unit of weight = 2,240 pounds (1,016 kg). Freight ton (measurement ton): Unit of volume = 40 cubic feet (~1.133 cubic meters). Shipping charges historically used whichever gave the higher value : weight or volume. Why? Some cargo is dense and heavy (iron ore, coal): charged by weight (long tons). Other cargo is bulky but light (cotton bales, furniture): charged by volume (freight tons). Example : 1,000 cubic feet of cotton = 25 freight tons (1,000 ÷ 40). If it weighs only 10,000 lbs = 4.46 long tons, ship charges for 25 freight tons (higher). Conversely, 1,000 cubic feet of lead = 25 freight tons. If it weighs 70,000 lbs = 31.25 long tons, ship charges for 31.25 long tons (higher). This "weight or measurement, whichever greater" rule persists in modern shipping (now using metric tonnes and cubic meters, but same principle).

8. How did metrication affect industries that relied on long tons?

Metrication required massive reengineering, retraining, and record conversion : Coal mining : Decades of production data in long tons had to be converted for comparisons. Miners trained to think in long tons had to learn metric. Modern equipment calibrated in tonnes. Shipping : Bills of lading, cargo manifests, freight rates all converted to metric tonnes. Crane capacities, ship specifications re-rated. Steel industry : Furnace capacities, production targets, quality standards converted. Historical production comparisons required conversion factors. Agriculture : Grain yields (tons per acre → tonnes per hectare), livestock weights, feed quantities. Challenges : Elderly workers unfamiliar with metric. "Rounding errors" in conversion causing disputes (1,000 long tons ≠ 1,000 tonnes). Cost of replacing scales, signage, documentation. Benefits : International trade simplified (no long ton/short ton confusion). Decimal calculations easier. Integration with scientific/engineering standards. Transition pain : 1970s-1990s saw dual labeling, calculation errors, generational confusion. By 2000s, mostly smooth, but legacy long ton data remains in archives requiring ongoing conversion skills.

9. Why do some sources say "ton" while others say "tonne"?

The spelling distinguishes metric from non-metric: "Ton" (t-o-n): Generic term, historically means long ton (UK), short ton (US), or any ton. "Tonne" (t-o-n-n-e): Specifically refers to metric ton (1,000 kg) . Also written "metric ton." The extra "ne" distinguishes it. Usage : British English : Often use "tonne" for metric, "ton" for Imperial/US. American English : Usually "ton" for short ton (domestic), "metric ton" (not "tonne") for 1,000 kg. International standards : SI prefers "tonne" for 1,000 kg to avoid confusion. Pronunciation : Both pronounced identically in English (sounds like "tun"). In practice : Context usually clarifies, but precise technical writing specifies: "long ton," "short ton," "metric tonne" (or "metric ton"). Ambiguity persists: A British naval historian might write "50,000 tons" meaning long tons, while a modern cargo manifest "50,000 tonnes" means metric. Recommendation: Always specify unit explicitly in technical contexts to prevent costly errors.

10. Can I still buy things by the long ton in the UK?

Legally : No, almost impossible. The Weights and Measures Act 1985 and subsequent regulations require most goods sold by weight to use metric units (kilograms, grams, tonnes). Imperial units can be supplementary (dual labeling), but metric must be primary. Violations result in fines. Exceptions : Some traditional items (loose goods in markets) tolerated Imperial informally, but legally must be metric. Practically : No modern British shop, supplier, or merchant sells bulk commodities by the long ton. Everything is tonnes (metric) : coal (if still sold for heating, rare), aggregates (gravel, sand), scrap metal, agricultural products. Why? : Suppliers, scales, invoices, and logistics all metric. Even older Britons who remember long tons accept metric in commercial contexts. Historical context : Pre-1970s, coal merchants delivered "1 ton of coal" (long ton) to homes. Now, heating oil sold in litres, firewood in cubic meters. Legacy : Long tons only appear in historical records, naval references, vintage engineering specs—not retail or commerce.

11. What industries were most resistant to abandoning the long ton?

Shipping and maritime industries were most resistant, for several reasons: 1. International standardization concerns : Shipping was already internationalized; changing units required global coordination. Royal Navy and Commonwealth navies valued continuity of displacement measurements across centuries for comparing ship classes. 2. Existing infrastructure : Shipyards, cranes, dry docks all rated in long tons. Re-rating everything expensive. 3. Cultural tradition : "Tonnage" terminology deeply embedded in maritime law, insurance, and practice. Changing felt like severing heritage. 4. Training : Mariners, naval architects, shipbuilders trained in long tons for entire careers. Coal industry also resisted: Miners, colliery managers, and coal merchants used long tons for generations. Production targets, wage calculations, and rail freight all based on long tons. However, resistance eventually failed : Economic necessity (international trade efficiency) and generational change (younger workers learned metric in school) gradually shifted all industries. By 2000s, even holdouts largely surrendered, with long tons surviving only in niche ceremonial contexts (Royal Navy traditions) and historical references.

12. How do I convert historical British data in long tons to modern metric?

Step-by-step conversion : 1. Identify that it's long tons : Historical British/Commonwealth data (pre-1990s) in "tons" almost certainly means long tons. Verify context (if US source, might be short tons). 2. Use precise conversion factor : 1 long ton = 1.01604691 metric tonnes (or 1,016.0469088 kg exactly). 3. Multiply : Long tons × 1.01604691 = metric tonnes. Example : 50 million long tons of coal (1913 UK production) × 1.01604691 = 50.802 million metric tonnes . 4. For large datasets : Use spreadsheet formula: =A1*1.01604691 where A1 is long tons. 5. Check reasonableness : Long ton is ~1.6% heavier than metric tonne, so metric number should be slightly larger. If wildly different, error likely. 6. Rounding : For historical approximation, 1 long ton ≈ 1 tonne (ignoring 1.6%) often acceptable. For trade/finance, use precise factor. 7. Document conversion : When publishing converted data, note: "Converted from long tons using factor 1.01604691." Common pitfall : Don't use 2,240 lbs → kg conversion (introduces rounding error). Use exact long ton to metric tonne factor.

Ton (UK) (long ton) - Unit Information & Conversion

Symbol:long ton

Plural:long tons

Category:Weight

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What is a Ton (UK)?

The UK ton, officially known as the long ton or imperial ton, is a unit of mass in the British Imperial system equal to exactly 2,240 pounds (1,016.0469088 kilograms). This measurement, approximately 1.6% larger than the metric tonne (1,000 kg) and 12% larger than the US short ton (2,000 lb), emerged from medieval British commerce and became standardized through the Weights and Measures Act of 1824. The long ton originated from the "tun," a large wine cask that held approximately 252 wine gallons and served as a standard unit in maritime trade. Historically dominant in British and Commonwealth shipping, coal trade, and bulk commodity markets, the long ton measured cargo capacity, ship displacement tonnage, and industrial materials throughout the British Empire's global commercial network. While largely replaced by the metric tonne in most Commonwealth nations following metrication in the 1960s-1980s, the long ton persists in specific maritime contexts (naval ship displacement in UK and Commonwealth navies), certain commodity markets (particularly in historical records), and traditional British industries. The term reflects Britain's centuries-long dominance of global maritime trade and the imperial measurement system's influence on international commerce before the worldwide adoption of the metric system.

History of the Ton (UK)

The long ton's origins trace to medieval English wine trade, where the "tun" (from Old English "tunne," meaning large cask) was a standard container holding 252 wine gallons (~954 liters) and weighing approximately 2,240 pounds when filled. By the 13th-14th centuries, merchants used "ton" as both a volume measure (for liquids) and weight measure (for bulk goods like wool, coal, and grain). Different commodities had various "ton" definitions, creating confusion in trade. The Weights and Measures Act of 1824 under King George IV standardized British weights, officially defining the imperial ton as 2,240 pounds (20 hundredweight of 112 pounds each), distinct from emerging American measurements. This "long ton" became the standard across the British Empire for shipping, coal mining, iron production, and international trade throughout the 19th-20th centuries. British dominance of global shipping made the long ton internationally recognized, used in bills of lading, cargo manifests, and maritime insurance. The British coal industry, which powered the Industrial Revolution, universally measured output in long tons. Naval architecture adopted displacement tonnage (weight of water displaced by a floating ship) measured in long tons, a practice continuing in Royal Navy and Commonwealth navies today. Following World War II, the metric system's adoption spread globally. The UK began metrication in 1965, and by the 1980s-1990s, most Commonwealth nations officially transitioned to metric tonnes for trade. However, certain maritime traditions and historical records preserve the long ton, and conversion between long tons and metric tonnes remains necessary when consulting pre-metrication documents, naval specifications, and vintage shipping records from the British Empire's commercial heyday.

Quick Answer

1 long ton (UK ton) = 2,240 pounds = 1,016.0469088 kilograms ≈ 1.016 metric tonnes

The long ton is approximately 12% heavier than the US short ton (2,000 lbs) and 1.6% heavier than the metric tonne (1,000 kg).

Quick Comparison Table

Weight Unit	Equals 1 Long Ton (UK Ton)
Pounds (lb)	2,240 lb (exactly)
Kilograms (kg)	1,016.0469088 kg (exactly)
Metric Tonnes (t)	1.01604691 t (~1.016 tonnes)
US Short Tons	1.12 short tons (2,000 lb = 1 short ton)
Ounces (oz)	35,840 oz (2,240 × 16)
Hundredweight (cwt, UK)	20 cwt (Imperial hundredweight = 112 lb)
Stones (UK)	160 stones (1 stone = 14 lb)
Grams	1,016,046.9088 grams

Key Relationships:

1 long ton = 1.12 short tons (long ton is 240 lbs heavier)
1 long ton ≈ 1.016 metric tonnes (long ton is ~16 kg heavier)
1 metric tonne ≈ 0.984 long tons (metric tonne is ~16 kg lighter)

Definition

The long ton (also called imperial ton or UK ton) is a unit of mass in the British Imperial system, officially defined as:

1 long ton = 2,240 pounds (lb) = 1,016.0469088 kilograms (kg)

Historical Definition

The long ton is based on the Imperial system's hundredweight (cwt):

1 long ton = 20 hundredweight (cwt)

1 hundredweight (Imperial) = 112 pounds
20 × 112 lb = 2,240 pounds

This contrasts with the US system:

US hundredweight = 100 pounds
US short ton = 20 US hundredweight = 2,000 pounds

The Three "Tons" Compared

Ton Type	Weight in Pounds	Weight in Kilograms	Where Used
Long Ton (UK/Imperial)	2,240 lb	1,016.047 kg	UK, Commonwealth (historic), naval displacement
Short Ton (US)	2,000 lb	907.185 kg	United States, North America
Metric Ton/Tonne	2,204.62 lb	1,000 kg (exactly)	International standard (SI-compatible)

Difference Summary:

Long ton vs. short ton: 240 lbs (10.9% difference)
Long ton vs. metric tonne: ~16 kg (1.6% difference)
Short ton vs. metric tonne: ~93 kg (10.2% difference)

Why "Long" Ton?

The term "long ton" emerged in the early 20th century to distinguish the British imperial ton (2,240 lbs) from the American "short ton" (2,000 lbs). Before this, "ton" simply meant the local standard:

In Britain and the Empire: ton = 2,240 lbs (now called "long ton")
In the United States: ton = 2,000 lbs (now called "short ton")

International trade requiring clarity led to the qualifying adjectives "long" and "short."

History of the Long Ton

Medieval Origins: The Tun (c. 1200-1500)

The Wine Trade:

The word "ton" derives from "tun" (Old English tunne, Middle English tonne), meaning a large cask or barrel
A tun was a standard wine cask in medieval England holding approximately 252 wine gallons (~954 liters, 210 Imperial gallons)
When filled with wine, a tun weighed roughly 2,240 pounds, establishing the weight association

Early Standardization Attempts:

13th-14th centuries: English merchants used "ton" for both volume (liquids) and weight (bulk goods)
Different commodities had varying ton definitions:
- Wool ton: Weight needed to fill shipping space (variable)
- Coal ton: Weight-based measurement
- Freight ton: Volume-based (40 cubic feet)

The Problem of Multiple Tons:

Confusion in trade due to inconsistent ton definitions
Disputes over cargo weight vs. volume
Regional variations across England and continental Europe

Standardization: The Weights and Measures Act of 1824

Imperial System Codification:

1824: British Parliament passed the Weights and Measures Act under King George IV
Unified and standardized British weights and measures across the Empire
Officially defined the imperial ton as 2,240 pounds
Based on existing practice: 20 hundredweight of 112 pounds each

Why 2,240 Pounds? The choice reflected established commercial practice:

1 hundredweight (cwt) = 112 pounds (8 stones × 14 pounds)
20 hundredweight = 2,240 pounds
This matched the traditional weight of a tun of wine
Integrated with existing Imperial units (stones, pounds, ounces)

Imperial Hundredweight System:

1 stone = 14 pounds
1 hundredweight = 8 stones = 112 pounds
1 ton = 20 hundredweight = 160 stones = 2,240 pounds

British Empire and Global Commerce (1824-1945)

Dominance of British Shipping:

19th century: Britain controlled ~60-70% of world merchant shipping tonnage
British shipping companies used long tons for:
- Cargo capacity (deadweight tonnage)
- Ship displacement (weight of water displaced)
- Freight charges (cost per ton)

The Coal Trade:

British coal powered the Industrial Revolution
Coal universally measured in long tons
Newcastle coal trade: Millions of long tons exported annually
Coal exports to Europe, Americas, Asia all priced in long tons

Naval Architecture:

Displacement tonnage: Weight of water displaced by a floating ship, measured in long tons
Used to classify warship size: "10,000-ton cruiser," "50,000-ton battleship"
Standard in Royal Navy and Commonwealth navies
Example: HMS Dreadnought (1906): ~18,000 long tons displacement

Imperial Commodity Trade:

Iron and steel: British iron production measured in long tons
Grain: Commonwealth grain shipments (wheat, barley) in long tons
Rubber, cotton, wool: Plantation exports measured in long tons
Freight rates: Shipping costs typically £X per long ton

Global Adoption:

British commercial dominance spread long ton usage
Bills of lading (shipping documents) in long tons
Maritime insurance: Cargo value calculated per long ton
Port records: Cargo throughput recorded in long tons

American Divergence: The Short Ton

US Measurement Evolution:

Early America inherited British Imperial units
By mid-19th century, US customary system diverged
Americans adopted a 100-pound hundredweight (simpler decimal-friendly base)
US ton = 20 US hundredweight = 20 × 100 lb = 2,000 pounds (the "short ton")

Why the Difference?

Simplicity: 100-pound hundredweight easier for calculation
Independence: Post-colonial desire for distinct American standards
Internal trade: US domestic commerce didn't require British compatibility

Terminology:

Originally, both were simply called "ton" in their respective countries
Early 20th century: International trade necessitated distinction
- British ton → "long ton"
- American ton → "short ton"

The Rise of the Metric Tonne (1875-Present)

Metric System Development:

1875: Metric Convention established international metric standards
Metric tonne (or ton) defined as 1,000 kilograms (exactly)
Decimal-based, simple, scientifically rational

Advantages Over Long/Short Tons:

Exact decimal definition: 1 tonne = 1,000 kg (no fractions)
Universal: Not tied to any national system
SI-compatible: Integrates with scientific units
Easier calculation: Decimal arithmetic vs. 2,240-pound conversions

Global Metrication Wave (1960s-1990s):

United Kingdom:

1965: UK government announced metrication program
1970s-1980s: Gradual transition in trade, industry, and commerce
1995: Most commercial transactions legally required to use metric units
Long ton legacy: Persists in road signs (distances/heights) and some traditional contexts

Commonwealth Nations:

Australia: Metrication 1970s, completed by 1988
Canada: Metrication 1970s, officially adopted 1977-1980
New Zealand: Metrication 1969-1976
India: Adopted metric system post-independence (1947-1960s)
South Africa: Metrication 1970s

Shipping and Maritime:

International Maritime Organization (IMO): Encouraged metric units
Modern cargo manifests typically in metric tonnes
Shipping contracts, freight rates increasingly metric

Contemporary Usage (1990s-Present)

Where the Long Ton Survives:

1. Naval Displacement (UK and Commonwealth):

Royal Navy still reports warship displacement in long tons (alongside metric)
Royal Australian Navy, Royal Canadian Navy, Royal New Zealand Navy: Use long tons traditionally
Example: HMS Queen Elizabeth aircraft carrier: ~65,000 long tons full load displacement

2. Historical Records:

Pre-1990s British commercial records in long tons
Archival shipping manifests, trade statistics, industrial production data
Converting historical data requires long ton knowledge

3. Certain Industries:

Some maritime insurance policies reference long tons in older contracts
Vintage engineering specifications (bridges, railways built pre-metrication)
Mining records: Historical coal, iron ore output

4. United States Context:

When Americans refer to British/Commonwealth historical data, they may encounter long tons
Rare in modern US usage (Americans use short tons domestically)

Gradual Obsolescence:

Most modern international trade: metric tonnes
Younger generations in UK/Commonwealth unfamiliar with long tons
Likely to become purely historical unit within decades

Real-World Examples of Long Tons in Action

1. Historical British Coal Industry

Peak Coal Production (1913):

UK coal output: 287 million long tons annually (highest ever)
Powered British industry, exported globally
Employed ~1 million miners

Coal Exports:

Late 19th century: Britain exported 50-70 million long tons/year
Destinations: Germany, France, Italy, Russia, South America, Asia
Priced in shillings per long ton at pithead or port

Domestic Use:

Household coal: Sold in hundredweights (112 lb) and tons (2,240 lb)
Industrial coal: Power stations, railways, steel mills bought in long tons
Railways: Steam locomotives consumed coal measured in long tons per mile

2. Ship Displacement Tonnage

Understanding Displacement:

A floating ship displaces water equal to its weight
Displacement tonnage = weight of displaced water, measured in long tons
Used to classify ship size and capacity

Famous Warships (Long Ton Displacement):

HMS Victory (1765, Nelson's flagship): ~3,500 long tons
HMS Dreadnought (1906, revolutionary battleship): ~18,000 long tons
HMS Hood (1920, battlecruiser): ~42,000 long tons standard, ~48,000 full load
HMS Vanguard (1946, last British battleship): ~44,500 long tons standard, ~51,420 full load
RMS Titanic (1912, passenger liner): ~46,329 gross register tons (different from displacement, but related)

Modern Royal Navy (Still Uses Long Tons):

HMS Queen Elizabeth (2017, aircraft carrier): ~65,000 long tons full load (~72,800 short tons, ~66,000 metric tonnes)
Type 45 destroyers: ~7,350 long tons full load

Why Displacement in Long Tons?

Tradition: Naval architecture historically British-dominated
Structural calculations: Ship's weight determines buoyancy, stability, and structural stress
Comparability: Allows comparison with historical ships

3. 19th-20th Century Industrial Production

Iron and Steel:

British iron production (1870): ~6 million long tons annually
Steel production (1913): ~7.7 million long tons
Priced and traded in long tons
Export statistics: Long tons to USA, Europe, Empire

Shipping Cargo Manifests:

Bills of lading listed cargo in long tons:
- "10,000 long tons of coal, Cardiff to Buenos Aires"
- "5,000 long tons of iron ore, Liverpool to New York"
Freight rates: £2 per long ton, for example

Railway Freight:

British railways tracked freight tonnage in long tons
1920s-1930s: Hundreds of millions of long tons of goods moved annually
Revenue calculated as ton-miles (long tons × miles)

4. Commonwealth Grain Trade

Canadian Wheat Exports (Early-Mid 20th Century):

Canada exported millions of long tons of wheat annually
Shipped from Vancouver, Montreal to UK and Europe
Grain elevator capacity measured in long tons

Australian Wool:

Australian wool production measured in long tons
Exported to British textile mills
Auction prices: Price per long ton of wool

Agricultural Statistics:

Pre-metrication agricultural yields: "X long tons of wheat per acre"
Livestock feed: "Y long tons of feed required annually"

5. British Engineering and Infrastructure

Bridge Load Ratings:

Victorian-era bridges rated in long tons
Example: "Maximum load: 20 long tons"
Modern conversions necessary for current use

Railway Specifications:

Steam locomotive weight: Measured in long tons
Example: LNER Class A4 (Mallard): ~165 long tons total weight
Freight car capacity: "10-ton wagon" (10 long tons)

Mining Equipment:

Ore wagons: Capacities in long tons
Conveyor systems: Throughput in long tons per hour

6. Maritime Shipping Terminology

Deadweight Tonnage (DWT):

Deadweight tonnage: Maximum cargo, fuel, provisions a ship can safely carry
Historically measured in long tons
Modern ships: Usually metric tonnes, but conversions to long tons common for historical comparison

Gross Tonnage (GT) vs. Displacement:

Gross tonnage: Volume-based measure (100 cubic feet = 1 gross ton, historically)
Displacement tonnage: Weight-based (long tons of water displaced)
Not directly comparable, but both called "tonnage"

Freight Ton vs. Long Ton:

Freight ton (measurement ton): 40 cubic feet of cargo space
Used for cargo that's voluminous but light (e.g., cotton bales)
Long ton: Weight, regardless of volume
Freight charged on whichever gives higher value: weight or volume

7. World War I and II Production

Munitions Production:

British shell production: Millions of long tons of explosives, steel casings
Shipbuilding: Liberty ships, warships measured in long tons
Example: "Britain produced 200,000 long tons of explosives in 1917"

U-Boat Warfare:

German submarines targeted Allied shipping
"Tonnage sunk" reported in long tons or gross register tons
Example: "U-boats sank 500,000 long tons of shipping in March 1943"

Strategic Bombing:

RAF/USAAF bomb tonnages sometimes reported in long tons
"10,000 long tons of bombs dropped on German cities in 1944"

Common Uses of the Long Ton in Modern Contexts

1. Naval and Maritime History

Researchers, naval historians, and museum curators working with historical ships and maritime records must understand long tons:

Ship specifications: Displacement, cargo capacity, fuel capacity
Archival documents: Shipping manifests, port records, naval reports
Comparative analysis: Comparing historical ships to modern vessels
Museum exhibits: HMS Victory, USS Constitution, RMS Titanic displays

Example: Understanding that HMS Hood's 42,000 long ton displacement = ~42,672 metric tonnes helps compare to modern carriers.

2. Royal Navy and Commonwealth Navies

British and Commonwealth naval forces still reference long tons:

Official displacement figures: Warships listed in long tons (with metric equivalent)
Naval doctrine: Historical continuity in naval architecture
Training: Naval officers learn both systems
Public relations: Press releases may include long ton figures for tradition

Modern Practice: Usually list both: "HMS Queen Elizabeth: 65,000 long tons (66,000 tonnes)"

3. Historical Research and Archives

Historians studying British Empire, Industrial Revolution, or maritime trade encounter long tons constantly:

Economic history: Production statistics (coal, iron, steel, ships)
Trade records: Import/export volumes
Infrastructure: Railway freight, canal cargo
Colonial economies: Plantation outputs (sugar, rubber, cotton)

Conversion Necessity: Comparing 19th-century British data (long tons) with modern data (metric tonnes) requires accurate conversion.

4. Vintage Engineering and Restoration

Engineers working with historic structures, machinery, or vehicles:

Bridge load ratings: Victorian bridges specified in long tons
Crane capacities: Historic cranes rated in long tons
Railway heritage: Steam locomotives, heritage railways use long tons
Industrial archaeology: Historic factories, mines with long ton specifications

Safety: Modern safety assessments must convert long ton ratings to metric.

5. Commodity Markets and Legal Documents

Occasionally, older contracts or legal documents reference long tons:

Mining leases: Historic coal, iron ore extraction rights
Shipping contracts: Old freight agreements still in force
Insurance policies: Maritime insurance with long ton clauses
Property deeds: Historical rights to extract/transport X long tons

Legal interpretation: Courts may need to convert long tons for enforcement.

6. Education and Reference

Students and general public encounter long tons in:

History textbooks: British industrial production, maritime trade
War histories: Shipping losses, munitions production
Biographies: Figures like Brunel (engineering), Nelson (naval)
Documentaries: Maritime history, industrial heritage

Confusion: Many confuse long ton, short ton, metric tonne without understanding differences.

7. International Trade (Rare, Legacy Contexts)

Very occasionally, long tons appear in:

UK-Commonwealth trade: Older business relationships honoring traditional units
Specific commodities: Niche markets with historical ties
Contracts: Long-standing agreements referencing long tons

Trend: Rapidly disappearing as metrication completes and older contracts expire.

How to Convert Long Tons to Other Weight Units

Basic Conversion Formulas

1 long ton = 2,240 pounds (lb) - EXACT
1 long ton = 1,016.0469088 kilograms (kg) - EXACT
1 long ton = 1.01604691 metric tonnes (t) - approximate
1 long ton = 1.12 US short tons - EXACT
1 long ton = 35,840 ounces (oz) - EXACT
1 long ton = 20 hundredweight (cwt, Imperial) - EXACT
1 long ton = 160 stones - EXACT

Reverse:
1 metric tonne = 0.984207 long tons
1 US short ton = 0.892857 long tons
1 kilogram = 0.000984207 long tons
1 pound = 0.000446429 long tons

Long Tons ↔ Other Weight Units

From	To	Multiply by
Long Tons	Pounds (lb)	× 2,240
Long Tons	Kilograms (kg)	× 1,016.0469088
Long Tons	Metric Tonnes (t)	× 1.01604691
Long Tons	US Short Tons	× 1.12
Long Tons	Ounces (oz)	× 35,840
Pounds	Long Tons	÷ 2,240
Kilograms	Long Tons	÷ 1,016.0469088
Metric Tonnes	Long Tons	÷ 1.01604691 (or × 0.984207)
US Short Tons	Long Tons	÷ 1.12 (or × 0.892857)

Examples

Example 1: HMS Queen Elizabeth Displacement

Displacement: 65,000 long tons (full load)
Convert to metric tonnes: 65,000 × 1.01604691 = 66,043 tonnes
Convert to US short tons: 65,000 × 1.12 = 72,800 short tons
Convert to kilograms: 65,000 × 1,016.0469088 = 66,043,049 kg

Example 2: British Coal Production (1913)

Production: 287 million long tons
Convert to metric tonnes: 287,000,000 × 1.01604691 = 291,605,463 tonnes
Convert to kilograms: 287,000,000 × 1,016.0469088 = 291,605,463,000 kg (291.6 million metric tonnes)

Example 3: Freight Shipment

Shipment: 5,000 long tons of iron ore
Convert to pounds: 5,000 × 2,240 = 11,200,000 pounds (11.2 million lbs)
Convert to metric tonnes: 5,000 × 1.01604691 = 5,080 tonnes
Convert to short tons: 5,000 × 1.12 = 5,600 US short tons

Example 4: Historical Railway Freight

Annual railway freight: 150 million long tons (1920s Britain)
Convert to metric tonnes: 150,000,000 × 1.01604691 = 152,407,037 tonnes

Example 5: Locomotive Weight

Steam locomotive: 100 long tons
Convert to kilograms: 100 × 1,016.0469088 = 101,605 kg (~102 tonnes)
Convert to pounds: 100 × 2,240 = 224,000 pounds

Common Conversion Mistakes to Avoid

1. ❌ Confusing Long Tons with Short Tons

Mistake: "The ship weighs 50,000 tons, which equals 50,000,000 kilograms."

Problem: If "ton" is long ton, the calculation is wrong. Must clarify which ton.

✅ Correct:

50,000 long tons = 50,802,345 kg (~50,802 metric tonnes)
50,000 short tons = 45,359,237 kg (~45,359 metric tonnes)
50,000 metric tonnes = 50,000,000 kg (exact)

Always specify: Long ton, short ton, or metric tonne.

2. ❌ Assuming "Ton" Equals 1,000 kg Everywhere

Mistake: "1 ton = 1,000 kg universally."

Problem: Only true for metric tonne. Long ton = 1,016 kg, short ton = 907 kg.

✅ Correct: Specify unit system:

Metric system: 1 tonne = 1,000 kg
Imperial system: 1 long ton = 1,016 kg
US customary: 1 short ton = 907 kg

3. ❌ Using Wrong Conversion Factor

Mistake: "To convert long tons to metric tonnes, multiply by 1.00."

Problem: Long ton is ~1.6% heavier. Correct factor: 1.01604691.

✅ Correct: 1 long ton = 1.01604691 metric tonnes (not 1.00).

Impact: For large quantities, 1.6% error is significant:

100,000 long tons ≈ 101,605 tonnes (not 100,000 tonnes)
Error: 1,605 tonnes (~£1-2 million in cargo value)

4. ❌ Confusing Displacement Tonnage with Cargo Capacity

Mistake: "The 10,000-ton warship can carry 10,000 tons of cargo."

Problem: Displacement tonnage = total weight of ship (hull + machinery + fuel + crew + cargo + weapons), not cargo capacity.

✅ Correct:

Displacement: Total weight (ship + everything on it)
Deadweight tonnage: Maximum cargo + fuel + stores the ship can carry
Cargo capacity: Actual cargo only (subset of deadweight)

Example: A 10,000-ton warship's hull, armor, engines, weapons might weigh 7,000 tons, leaving 3,000 tons for fuel, ammunition, stores, crew.

5. ❌ Mixing Gross Tonnage with Weight Tonnage

Mistake: "The ship is 50,000 gross tons, so it weighs 50,000 long tons."

Problem: Gross tonnage (GT) is a volume measure (internal capacity), not weight.

✅ Correct:

Gross tonnage: Volume-based (100 cubic feet = 1 gross ton, historically)
Displacement tonnage: Weight-based (long tons of water displaced)
Different numbers: A ship can be 50,000 GT but only 40,000 tons displacement, or vice versa

6. ❌ Forgetting That Hundredweight Differs Between UK and US

Mistake: "20 hundredweight = 1 ton, so 1 cwt = 100 pounds."

Problem: True for US, false for UK Imperial system.

✅ Correct:

Imperial (UK): 1 cwt = 112 lb, so 20 cwt = 2,240 lb (long ton)
US: 1 cwt = 100 lb, so 20 cwt = 2,000 lb (short ton)

Ton (UK) Conversion Formulas

To Kilogram:

1 long ton = 1016.046909 kg

Example: 5 long tons = 5080.234544 kilograms

To Gram:

1 long ton = 1016046.9088 g

Example: 5 long tons = 5080234.544 grams

To Milligram:

1 long ton = 1016046908.8 mg

Example: 5 long tons = 5080234544 milligrams

To Pound:

1 long ton = 2240 lb

Example: 5 long tons = 11200 pounds

To Ounce:

1 long ton = 35840.000032 oz

Example: 5 long tons = 179200.000158 ounces

To Stone:

1 long ton = 160 st

Example: 5 long tons = 800 stones

To Ton (metric):

1 long ton = 1.016047 t

Example: 5 long tons = 5.080235 tons

To Ton (US):

1 long ton = 1.12 ton

Example: 5 long tons = 5.6 US tons

To Microgram:

1 long ton = 1016046908799.9999 µg

Example: 5 long tons = 5080234544000 micrograms

To Carat:

1 long ton = 5080234.544 ct

Example: 5 long tons = 25401172.72 carats

To Slug:

1 long ton = 69.621342 sl

Example: 5 long tons = 348.106712 slugs

To Troy Ounce:

1 long ton = 32666.666667 oz t

Example: 5 long tons = 163333.333333 troy ounces

To Pennyweight:

1 long ton = 653333.333333 dwt

Example: 5 long tons = 3266666.666667 pennyweights

To Grain:

1 long ton = 15680000 gr

Example: 5 long tons = 78400000 grains

To Dram:

1 long ton = 573440 dr

Example: 5 long tons = 2867200 drams

To Quintal:

1 long ton = 10.160469 q

Example: 5 long tons = 50.802345 quintals

To Atomic Mass Unit:

1 long ton = N/A u

Example: 5 long tons = N/A atomic mass units

To Pavan (India):

1 long ton = 127005.8636 pavan

Example: 5 long tons = 635029.318 pavan

To Kati (India):

1 long ton = 87109.645816 kati

Example: 5 long tons = 435548.229081 kati

To Masha (India):

1 long ton = 1114819.956989 masha

Example: 5 long tons = 5574099.784946 masha

To Dina (India):

1 long ton = 15680000000 dina

Example: 5 long tons = 78400000000 dina

To Pras (India):

1 long ton = 364148415454.0893 pras

Example: 5 long tons = 1820742077270.4465 pras

To Lota (India):

1 long ton = N/A lota

Example: 5 long tons = N/A lota

Frequently Asked Questions

There are exactly 2,240 pounds in 1 UK long ton. This derives from the Imperial system's definition: 1 long ton = 20 hundredweight, and 1 Imperial hundredweight = 112 pounds, so 20 × 112 = 2,240 pounds. This standard was codified in the British Weights and Measures Act of 1824 and became the official weight unit across the British Empire for shipping, coal trade, and bulk commodities. The 2,240-pound long ton originated from the traditional weight of a "tun" (large wine cask) when filled, which medieval merchants found convenient for maritime commerce. Today, while largely replaced by metric tonnes in most contexts, the 2,240-pound definition remains unchanged in the few areas where long tons are still used, particularly Royal Navy ship displacement measurements.

Convert Ton (UK)

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Ton (UK) (long ton) - Unit Information & Conversion

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What is a Ton (UK)?

History of the Ton (UK)

Quick Answer

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Definition

Historical Definition

The Three "Tons" Compared

Why "Long" Ton?

History of the Long Ton

Medieval Origins: The Tun (c. 1200-1500)

Standardization: The Weights and Measures Act of 1824

British Empire and Global Commerce (1824-1945)

American Divergence: The Short Ton

The Rise of the Metric Tonne (1875-Present)

Contemporary Usage (1990s-Present)

Real-World Examples of Long Tons in Action

1. Historical British Coal Industry

2. Ship Displacement Tonnage

3. 19th-20th Century Industrial Production

4. Commonwealth Grain Trade

5. British Engineering and Infrastructure

6. Maritime Shipping Terminology

7. World War I and II Production

Common Uses of the Long Ton in Modern Contexts

1. Naval and Maritime History

2. Royal Navy and Commonwealth Navies

3. Historical Research and Archives

4. Vintage Engineering and Restoration

5. Commodity Markets and Legal Documents

6. Education and Reference

7. International Trade (Rare, Legacy Contexts)

How to Convert Long Tons to Other Weight Units

Basic Conversion Formulas

Long Tons ↔ Other Weight Units

Examples

Common Conversion Mistakes to Avoid

1. ❌ Confusing Long Tons with Short Tons

2. ❌ Assuming "Ton" Equals 1,000 kg Everywhere

3. ❌ Using Wrong Conversion Factor

4. ❌ Confusing Displacement Tonnage with Cargo Capacity

5. ❌ Mixing Gross Tonnage with Weight Tonnage

6. ❌ Forgetting That Hundredweight Differs Between UK and US

Ton (UK) Conversion Formulas

Frequently Asked Questions

1. How many pounds are in a UK Ton (Long Ton)?

2. Is a UK Ton larger than a US Ton?

3. How does the UK Ton compare to the metric ton?

4. Why did Britain use 2,240 pounds instead of a round number?

5. Do modern British ships still use long tons?

6. When did the UK stop using long tons officially?

7. What's the difference between a long ton and a freight ton?

8. How did metrication affect industries that relied on long tons?

9. Why do some sources say "ton" while others say "tonne"?

10. Can I still buy things by the long ton in the UK?

11. What industries were most resistant to abandoning the long ton?

12. How do I convert historical British data in long tons to modern metric?

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