Square Mile to Hectare Converter
Convert square miles to hectares with our free online area converter.
Quick Answer
1 Square Mile = 258.998811 hectares
Formula: Square Mile × conversion factor = Hectare
Use the calculator below for instant, accurate conversions.
Our Accuracy Guarantee
All conversion formulas on UnitsConverter.io have been verified against NIST (National Institute of Standards and Technology) guidelines and international SI standards. Our calculations are accurate to 10 decimal places for standard conversions and use arbitrary precision arithmetic for astronomical units.
Square Mile to Hectare Calculator
How to Use the Square Mile to Hectare Calculator:
- Enter the value you want to convert in the 'From' field (Square Mile).
- The converted value in Hectare will appear automatically in the 'To' field.
- Use the dropdown menus to select different units within the Area category.
- Click the swap button (⇌) to reverse the conversion direction.
How to Convert Square Mile to Hectare: Step-by-Step Guide
Converting Square Mile to Hectare involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
1 Square Mile = 258.9988 hectaresExample Calculation:
Convert 10 square miles: 10 × 258.9988 = 2589.988 hectares
Disclaimer: For Reference Only
These conversion results are provided for informational purposes only. While we strive for accuracy, we make no guarantees regarding the precision of these results, especially for conversions involving extremely large or small numbers which may be subject to the inherent limitations of standard computer floating-point arithmetic.
Not for professional use. Results should be verified before use in any critical application. View our Terms of Service for more information.
Need to convert to other area units?
View all Area conversions →What is a Square Mile and a Hectare?
and Standards
Mathematical Definition
The square mile (symbol: mi², alternative: sq mi) is a unit of area in the Imperial and US Customary systems, defined as:
The area of a square whose sides each measure exactly one statute mile in length.
Formula: $$ 1 \text{ mi}^2 = 1 \text{ mile} \times 1 \text{ mile} $$
Fundamental Relationships
Within the Imperial/US System:
- 1 mile = 5,280 feet (ft) = 1,760 yards (yd)
- 1 mi² = (5,280 ft)² = 27,878,400 ft²
- 1 mi² = (1,760 yd)² = 3,097,600 yd²
- 1 mi² = 640 acres (fundamental definition)
The 640-Acre Relationship: This is not arbitrary. The US survey system was designed so that:
- 1 section = 1 square mile = 640 acres
- ½ section = 320 acres
- ¼ section = 160 acres (historically a "homestead" size)
- ⅛ section = 80 acres
- 1/16 section = 40 acres
Metric Conversions (Exact):
Based on the 1959 International Yard and Pound Agreement:
- 1 mile = 1.609344 kilometers (exactly)
- 1 mi² = (1.609344 km)² = 2.58998811033 6 km²
Practical Metric Conversions:
- 1 mi² ≈ 2.59 km² (rounded)
- 1 mi² = 258.999 hectares ≈ 259 ha
- 1 mi² = 2,589,988 square meters
Visual Representation
A perfect square mile:
- Each side: 5,280 feet = 1.609 km
- Perimeter: 4 miles = 21,120 feet = 6.44 km
- Diagonal: 1.414 miles = 7,470 feet = 2.28 km
How big is it?
- About 505 soccer fields (FIFA regulation)
- About 484 American football fields (including end zones)
- About 1,280 city blocks (assuming 200 ft × 200 ft blocks)
- A 10-minute walk from one side to the opposite side
and Standards
The hectare is defined as an area of exactly 10,000 square meters:
1 ha = 10,000 m² = 100 m × 100 m
Precise Equivalents
- 1 ha = 10,000 m² (exactly, by definition)
- 1 ha = 0.01 km² = 1/100 square kilometer (exactly)
- 1 ha = 100 ares (where 1 are = 100 m²)
- 1 ha = 1 hm² (square hectometer)
- 1 ha = 2.47105 acres (US survey/international)
- 1 ha = 107,639.1 square feet
- 1 ha = 11,959.9 square yards
- 1 ha = 15,500,000 square inches
The hectare derives from the are (symbol: a), a rarely used metric unit defined as 100 m². The prefix hecto- means "hundred," so hectare literally means "hundred ares."
SI Status
The hectare is not an official SI unit—the SI unit of area is the square meter (m²). However, the International Bureau of Weights and Measures (BIPM) explicitly lists the hectare as a non-SI unit accepted for use with the SI in its SI Brochure, recognizing its overwhelming practical importance in land measurement globally.
Metric Prefixes and Multiples
While technically compatible with metric prefixes, only a few are used in practice:
- Decare (daa) = 0.1 ha = 1,000 m² (used in some Eastern European and Middle Eastern countries)
- Hectare (ha) = 1 ha = 10,000 m² (standard unit)
- Square kilometer (km²) = 100 ha (preferred for very large areas)
The centiare (1 m²) and are (100 m²) exist theoretically but are rarely used today.
Note: The Square Mile is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Hectare belongs to the imperial/US customary system.
History of the Square Mile and Hectare
and Evolution
The Roman Mile (Ancient Origins)
The word "mile" comes from the Latin "mille passus" (thousand paces).
Roman Definition:
- 1 pace (passus) = 2 steps = 5 Roman feet (pes)
- 1,000 paces = 5,000 Roman feet = 1 Roman mile
- 1 Roman mile ≈ 4,850 modern feet (about 1,480 meters)
Roman Land Measurement:
- Romans used the jugerum (about 2/3 acre) for agricultural land
- Centuriation: land divided into square grids for colonial settlements
- This grid system influenced later European land survey methods
Medieval England: Mile Chaos (500-1500 AD)
Multiple "Miles" Existed Simultaneously:
- Old London Mile: 5,000 feet
- Irish Mile: 6,720 feet (2.048 km)
- Scottish Mile: 5,952 feet (1.814 km)
- Various local miles: ranged from 4,800 to 7,000 feet
Why the confusion?
- Different regions had different "feet" lengths
- Local lords defined their own measurement standards
- Trade and legal disputes were common
The Statute Mile (1593)
Queen Elizabeth I's Parliament (1593):
- Standardized the statute mile at exactly 5,280 feet
- Made it the official measurement for England
- Named "statute" because it was defined by statute (law)
Why 5,280 feet?
- 1 mile = 8 furlongs (furlong = 660 feet, used in agriculture)
- 1 furlong = 10 chains (chain = 66 feet, standard surveyor's chain)
- This made conversions between agricultural measures convenient
Square Mile Standardization:
- As the statute mile was defined, the square mile naturally followed
- 1 mi² = 640 acres (this relationship was crucial for land sales)
British Empire and Colonial Land Surveys (1600s-1800s)
Square Mile in Colonial Administration:
- Used throughout British Empire for measuring:
- Colonial territories
- Land grants to settlers
- Administrative districts
- Natural resources (forests, mining claims)
Challenges:
- Early surveys often inaccurate (limited technology)
- Terrain (mountains, rivers) made perfect square miles impossible
- Native land claims conflicted with colonial grid systems
US Public Land Survey System (1785)
The Land Ordinance of 1785:
Perhaps the most important application of the square mile in history.
Problem: The newly independent United States owned vast unsurveyed western territories (Northwest Territory: modern Ohio, Indiana, Illinois, Michigan, Wisconsin, and part of Minnesota).
Solution: Congress passed the Land Ordinance of 1785, creating a systematic survey grid.
The System:
Township: 6 miles × 6 miles = 36 square miles
- Divided into 36 sections
- Each section numbered 1-36 (specific numbering pattern)
Section: 1 mile × 1 mile = 1 square mile = 640 acres
- The fundamental unit of sale
- Could be subdivided: half-section (320 ac), quarter-section (160 ac), etc.
Quarter-Section: ½ mile × ½ mile = 160 acres
- Became the standard homestead size (Homestead Act of 1862)
- Considered sufficient for a family farm
Impact:
- Surveyed over 1.5 billion acres (2.3 million square miles)
- Used in 30 US states (primarily west of the Ohio River)
- Created the rectangular field patterns visible from aircraft today
- Property descriptions still use this system: "SW¼ of Section 12, Township 3N, Range 4W"
States Using PLSS: Alabama, Alaska, Arizona, Arkansas, California, Colorado, Florida, Idaho, Illinois, Indiana, Iowa, Kansas, Louisiana, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Mexico, North Dakota, Ohio, Oklahoma, Oregon, South Dakota, Utah, Washington, Wisconsin, Wyoming
States NOT Using PLSS (Original 13 colonies plus Texas, Hawaii, Kentucky, Tennessee, Vermont, West Virginia): These states used metes and bounds surveying (descriptive: "from the oak tree to the creek to the stone wall...").
International Yard Agreement (1959)
Standardization of the Yard/Foot/Mile:
- US, UK, Canada, Australia, New Zealand, South Africa agreed
- 1 yard = 0.9144 meters (exactly)
- 1 foot = 0.3048 meters (exactly)
- 1 mile = 1.609344 kilometers (exactly)
- 1 square mile = 2.589988110336 km² (exactly)
Why This Mattered:
- International scientific cooperation required consistent units
- Engineering projects crossing borders needed standards
- Eliminated minor differences between US and UK definitions
US Survey Foot Exception:
- US kept the "US survey foot" (1 ft = 1200/3937 m) for existing land records
- Difference: 2 parts per million (0.0002%)
- Matters for large-scale surveys spanning many miles
- Most states switched to international foot by 2023
Modern Era: Metrication and Persistence (1960-Present)
Global Metrication:
- 1965: UK began metrication (Ordnance Survey switched to km²)
- 1970: Canada officially metricated
- 1975: Australia completed metrication
- 1985: New Zealand fully metricated
US Resistance:
- Metric Conversion Act (1975): voluntary metrication—failed
- Square mile remains standard for US geography, census, planning
- All US atlases, maps, and official statistics use square miles
- Real estate still uses acres and square feet
Current Usage:
- United States: Exclusive standard for geographical areas
- United Kingdom: Mixed use (km² official, mi² still common)
- Canada: km² official, mi² understood by older generations
- Myanmar: Uses square mile
- Liberia: Uses square mile
International Organizations:
- UN, WHO, World Bank: use km²
- US Census Bureau: uses mi²
- CIA World Factbook: provides both mi² and km²
and Evolution
The French Revolution and the Birth of the Metric System (1790s)
The hectare emerged from the revolutionary fervor of 1790s France. The French Revolution sought to overthrow not only the monarchy but also the chaotic patchwork of traditional measurement units that varied by region, trade, and lord. Land measurement was particularly inconsistent: the arpent varied from 34 to 51 ares depending on locality, and dozens of other regional land units created confusion and inequity.
In 1795, the revolutionary government adopted the metric system, including the are as the fundamental unit of land area, defined as 100 square meters (a square 10 meters on each side). The hectare ("hundred ares") was immediately created as a larger, more practical unit for agricultural land, equal to 10,000 square meters—a square 100 meters on each side.
The Triumph of the Hectare over the Are (19th Century)
While the are was the official base unit, it proved awkwardly small for practical agriculture and forestry. A typical farm field might be dozens or hundreds of ares. The hectare, by contrast, was the perfect size: small enough to measure individual fields precisely, large enough to describe farm sizes conveniently. Within decades, the hectare became the dominant unit, and the are faded into obscurity.
Key milestone: In 1879, the International Committee for Weights and Measures (CIPM) formally adopted the hectare for international use, cementing its status as the global standard for land measurement.
Global Metrication: The Hectare Spreads Worldwide (1800s-1900s)
As the metric system spread from France across Europe, Latin America, and eventually Asia and Africa, the hectare went with it:
- 1800s: Adopted across continental Europe (Germany, Italy, Spain, Netherlands, Scandinavia)
- 1900-1950: Latin American countries metricated (Argentina, Brazil, Mexico, Chile)
- 1950-1980: Post-colonial nations in Africa and Asia adopted the metric system, including the hectare (India, Indonesia, Nigeria, Kenya)
- 1970s: Australia and New Zealand officially switched from acres to hectares
- 1980s-present: Even partially metricated countries like Canada and the UK increasingly use hectares for official land statistics
Modern status: As of 2025, the hectare is the primary land measurement unit in over 170 countries, representing more than 95% of the world's population and land area.
Notable Holdouts and Hybrid Systems
United States: Continues to use acres almost exclusively for land measurement, despite metrication in science and industry.
United Kingdom: Officially metricated in the 1990s, but acres persist in casual speech, real estate listings, and tradition. Government statistics use hectares, while property advertisements often show both units.
Myanmar: Uses traditional Burmese land units alongside acres; hectares are rare.
Canada: Officially metricated (hectares), but older Canadians and rural areas often still reference acres informally.
The Hectare in International Agriculture and Forestry
By the mid-20th century, international organizations standardized on the hectare:
- FAO (Food and Agriculture Organization): Reports global agricultural data in hectares
- World Bank: Land area statistics in hectares
- IPCC and climate science: Forest cover, deforestation, and carbon storage measured in hectares
- International land treaties: Boundary agreements, protected areas, and resource rights defined in hectares
The hectare's dominance in these domains ensures its continued relevance even in non-metric countries, where professionals in agriculture, forestry, and environmental science routinely convert between acres and hectares.
Common Uses and Applications: square miles vs hectares
Explore the typical applications for both Square Mile (imperial/US) and Hectare (imperial/US) to understand their common contexts.
Common Uses for square miles
Across Industries
1. Government and Census
US Census Bureau:
- Reports all geographic areas in square miles
- Population density: people per mi²
- Urban area definitions based on mi² thresholds
- Metropolitan Statistical Areas (MSAs) measured in mi²
Land Management:
- Bureau of Land Management (BLM): 247 million acres = 386,000 mi²
- US Forest Service: 193 million acres = 302,000 mi²
- National Park Service: 84 million acres = 131,000 mi²
2. Geography and Cartography
Map Making:
- US Geological Survey (USGS) maps use mi²
- Topographic maps scale in miles
- GIS software in US defaults to square miles
Geographic Information Systems (GIS):
- Area calculations reported in mi² for US audiences
- Spatial analysis uses mi² for US jurisdictions
3. Urban Planning and Development
City Planning:
- Zoning maps measured in mi²
- Service area calculations (fire, police, schools) in mi²
- Transit system coverage in mi²
Infrastructure:
- Road networks: lane-miles (length × lanes)
- Service territories: utilities measured in mi²
- Emergency response zones: mi² coverage areas
4. Real Estate (Large Tracts)
Rural Land Sales:
- Ranches: sometimes listed in mi² (though acres more common)
- Large timber tracts: mi²
- Mining claims: sections (1 mi² = 640 acres)
Commercial Development:
- Master-planned communities: hundreds to thousands of acres (multiple mi²)
- Industrial parks: often measured in mi²
5. Environmental Science and Conservation
Habitat Measurement:
- Wildlife refuges measured in mi²
- Conservation easements: large tracts in mi²
- Wetland restoration projects: mi²
Disaster Assessment:
- Wildfire extent: acres or mi²
- Flood zones: mi² inundated
- Hurricane damage: mi² affected
When to Use hectares
1. Agriculture: Farm Sizes and Crop Yields
The hectare is the universal standard for agricultural land measurement worldwide (except in the US). Farm sizes, field areas, crop yields, and agricultural statistics are expressed in hectares.
Crop yields are standardized as metric tons per hectare (t/ha) or kilograms per hectare (kg/ha):
- Wheat: 3-10 t/ha (depending on region and farming intensity)
- Rice: 4-8 t/ha
- Corn (maize): 8-15 t/ha
- Soybeans: 2-5 t/ha
Example: A 50-hectare wheat farm yielding 5 t/ha produces 250 metric tons of wheat annually.
2. Forestry: Timber Yields and Forest Management
Forestry professionals measure forest areas, logging concessions, reforestation projects, and timber yields in hectares.
Timber yield is expressed as cubic meters per hectare (m³/ha):
- Temperate softwood forest: 150-400 m³/ha
- Tropical rainforest: 200-600 m³/ha
- Boreal forest: 80-200 m³/ha
Example: A sustainable logging operation might harvest 5 m³/ha/year from a 1,000-hectare forest, yielding 5,000 m³ of timber annually.
3. Urban Planning: Zoning and Development
Urban planners use hectares to measure development sites, zoning areas, and infrastructure projects. Residential density is often expressed as dwellings per hectare (dw/ha) or persons per hectare (pp/ha).
Typical densities:
- Suburban single-family: 10-25 dw/ha
- Urban townhouses: 30-60 dw/ha
- Mid-rise apartments: 100-200 dw/ha
- High-rise urban core: 300-1,000+ dw/ha
Example: A 20-hectare mixed-use development with an average density of 80 dw/ha would contain 1,600 dwellings.
4. Real Estate: Land Sales and Property Listings
In metricated countries, land parcels are listed in hectares. Small properties (under 1 ha) may be listed in square meters, while large rural properties use hectares.
Example listing: "50-hectare vineyard estate in Tuscany, fully planted, irrigation, farmhouse included."
In hybrid countries like the UK and Canada, listings often show both units: "25 hectares (62 acres)."
5. Environmental Science: Protected Areas and Deforestation
Conservation organizations, national parks, and environmental treaties use hectares to define protected areas, measure deforestation, and calculate carbon storage.
Carbon storage in forests is measured as metric tons of CO₂ equivalent per hectare (tCO₂e/ha):
- Tropical rainforest: 200-600 tCO₂e/ha
- Temperate forest: 100-300 tCO₂e/ha
- Boreal forest: 50-150 tCO₂e/ha
Example: Protecting 10,000 hectares of Amazon rainforest prevents release of ~4,000,000 metric tons of CO₂.
6. International Development and Food Security
The Food and Agriculture Organization (FAO), World Bank, and UN agencies report agricultural land, arable land per capita, and food production in hectares.
Arable land per capita (global average): ~0.19 ha per person (2025)
- High: Australia ~1.9 ha/person, Canada ~1.2 ha/person
- Low: Bangladesh ~0.05 ha/person, China ~0.08 ha/person
Food security context: Feeding one person for a year requires approximately 0.2-0.3 ha of arable land (depending on diet and farming intensity).
Additional Unit Information
About Square Mile (mi²)
How many acres are in one square mile?
Exactly 640 acres in one square mile. This is a fundamental relationship in the Imperial and US Customary systems.
Historical Origin:
- 1 acre = 1 furlong × 1 chain = 660 ft × 66 ft = 43,560 ft²
- 1 mile = 8 furlongs = 5,280 ft
- 1 mi² = (8 furlongs)² = 64 acres × 10 = 640 acres
Common Subdivisions:
- 1 mi² = 640 acres (full section)
- ½ mi² = 320 acres (half section)
- ¼ mi² = 160 acres (quarter section, homestead)
- ⅛ mi² = 80 acres
- 1/16 mi² = 40 acres
How many square kilometers are in one square mile?
One square mile equals approximately 2.59 square kilometers (2.58998811 km² exactly).
Conversion Formula: $$ 1 \text{ mi}^2 = 2.58998811 \text{ km}^2 $$
Quick Mental Math: Multiply mi² by 2.6
Examples:
- 100 mi² = 259 km²
- 1,000 mi² = 2,590 km²
- 10,000 mi² = 25,900 km²
What is a "section" of land in the US?
In the US Public Land Survey System (PLSS), a section is a unit of land area nominally equivalent to one square mile (640 acres).
Township Organization:
- 1 township = 36 sections arranged in a 6×6 grid
- Each section numbered 1-36 (specific pattern)
- Section 16 often reserved for schools (in original PLSS states)
Legal Land Descriptions:
- "SW¼ of Section 12, Township 3 North, Range 4 West" = 160 acres
- This system used in 30 US states
Actual vs Nominal:
- Sections are "nominally" 1 mi² due to survey errors and Earth's curvature
- Actual sections: typically 635-645 acres
- "Government lots" used to correct discrepancies
Is the square mile an SI unit?
No, the square mile is not part of the International System of Units (SI). It belongs to the British Imperial and US Customary systems.
SI/Metric Equivalents:
- Square kilometer (km²): SI standard for large areas
- Hectare (ha): Accepted for use with SI, especially agriculture
Global Usage:
- US: square miles standard
- UK: mixed (km² official, mi² common)
- Rest of world: almost exclusively km²
How do you visualize a square mile?
Walking Measure:
- 1 mile ≈ 20-minute walk at average pace
- Walking around a square mile: 4 miles = 80-minute walk
Grid Measure:
- Imagine 8 city blocks × 8 city blocks (if blocks are 660 ft)
- About 1,280 standard city blocks (if blocks are 200 ft × 200 ft)
Sports Fields:
- About 484 American football fields (with end zones)
- About 505 FIFA regulation soccer fields
- About 740 standard baseball diamonds
Urban Comparison:
- Downtown core of a medium city
- Major university campus
- Large shopping mall with parking lots
How big is Central Park in square miles?
Central Park (NYC): 1.317 mi² (3.41 km²) = 843 acres
Comparisons:
- 1.3× larger than a standard section
- About 6% of Manhattan's area
- Slightly larger than Monaco (0.78 mi²)
Other Famous Parks:
- Golden Gate Park (SF): 1.017 mi² (2.63 km²)
- Griffith Park (LA): 6.9 mi² (17.9 km²)
- Rock Creek Park (DC): 2.8 mi² (7.2 km²)
What is population density per square mile?
Population density is the number of people per unit area, commonly expressed as people per square mile in the US.
Formula: $$ \text{Density} = \frac{\text{Population}}{\text{Area (mi}^2\text{)}} $$
Example:
- San Francisco: 873,965 people ÷ 47 mi² = 18,595 people/mi²
Density Categories:
- Very high: >10,000 people/mi² (Manhattan: 74,000/mi²)
- High: 5,000-10,000 people/mi² (most urban cores)
- Moderate: 1,000-5,000 people/mi² (suburbs)
- Low: 100-1,000 people/mi² (rural-suburban)
- Very low: <100 people/mi² (rural)
How many square miles is Earth's surface?
Total Earth Surface: 196.9 million mi² (510.1 million km²)
Breakdown:
- Land area: 57.5 million mi² (148.9 million km²) — 29.2%
- Water area: 139.4 million mi² (361.1 million km²) — 70.8%
Continents (Land):
- Asia: 17.2 million mi² (44.6 million km²)
- Africa: 11.7 million mi² (30.4 million km²)
- North America: 9.5 million mi² (24.7 million km²)
- South America: 6.9 million mi² (17.8 million km²)
- Antarctica: 5.5 million mi² (14.2 million km²)
- Europe: 3.9 million mi² (10.2 million km²)
- Australia/Oceania: 3.3 million mi² (8.5 million km²)
Can square miles measure ocean areas?
Yes, square miles can measure ocean areas, though square kilometers are more common internationally.
Oceans by Area:
- Pacific Ocean: 63.8 million mi² (165.2 million km²) — largest
- Atlantic Ocean: 41.1 million mi² (106.5 million km²)
- Indian Ocean: 27.2 million mi² (70.6 million km²)
- Southern Ocean: 7.8 million mi² (20.3 million km²)
- Arctic Ocean: 5.4 million mi² (14.1 million km²) — smallest
Comparison:
- Pacific Ocean alone is larger than all land on Earth combined
What is the area of the continental United States?
Continental (Contiguous) United States: 3,119,885 mi² (8,080,464 km²)
This includes the "Lower 48" states (excludes Alaska and Hawaii).
Breakdown:
- Land area: 2,959,064 mi² (7,663,941 km²)
- Water area: 160,821 mi² (416,522 km²)
Total United States (All 50 states):
- Total area: 3,796,742 mi² (9,833,520 km²)
- Alaska adds 665,384 mi² (1,723,337 km²)
- Hawaii adds 10,931 mi² (28,311 km²)
About Hectare (ha)
How large is a hectare visually?
A hectare is 10,000 square meters, or a square 100 meters on each side.
Visual comparisons:
- 1.4 FIFA soccer fields (a standard soccer pitch is ~7,140 m², so 1 ha ≈ 1.4 pitches)
- Slightly larger than a rugby union pitch (max 100m × 70m = 7,000 m²)
- About 2.5 times an American football field (with end zones: ~5,350 m²)
- Trafalgar Square, London is approximately 1 hectare
Walking it: Walking around the perimeter of a 1-hectare square (400 meters total) takes about 5 minutes at a normal pace.
Running it: A 100m × 100m square has a perimeter of 400 meters—exactly the distance of a standard running track lap.
How many square meters are in a hectare?
Exactly 10,000 square meters (m²) in one hectare.
Formula: m² = ha × 10,000
Examples:
- 0.1 ha = 1,000 m²
- 1 ha = 10,000 m²
- 5 ha = 50,000 m²
- 100 ha = 1,000,000 m² = 1 km²
What is an "are" and how does it relate to a hectare?
The are (symbol: a) is a metric unit of area defined as 100 square meters—a square 10 meters on each side.
Relationship: 1 hectare = 100 ares
The are was the original base unit of land measurement in the metric system (1795), but the hectare (100 ares) proved more practical for actual use. Today, the are is obsolete in most countries, though it persists in legal documents and some rural areas of France and Switzerland.
Related unit: The decare (daa) = 10 ares = 1,000 m² = 0.1 ha, still used in Greece, Turkey, Bulgaria, and some Middle Eastern countries.
How many acres are in a hectare?
One hectare equals approximately 2.47105 acres (or more precisely, 2.4710538 acres).
Formula: acres = ha × 2.47105
Common conversions:
- 1 ha = 2.47 acres
- 10 ha = 24.71 acres
- 100 ha = 247.1 acres
- 0.5 ha = 1.24 acres
Reverse: 1 acre = 0.4047 hectares
Memory aid: "A hectare is about two and a half acres."
How many hectares are in a square kilometer?
Exactly 100 hectares in one square kilometer.
Formula: ha = km² × 100
Why: 1 km² = 1,000 m × 1,000 m = 1,000,000 m². And 1 ha = 10,000 m². So 1,000,000 ÷ 10,000 = 100.
Examples:
- 0.01 km² = 1 ha
- 0.5 km² = 50 ha
- 1 km² = 100 ha
- 10 km² = 1,000 ha
Large areas: For areas over ~10,000 ha (100 km²), square kilometers become more convenient than hectares.
Is the hectare an official SI unit?
No, the hectare is not an official SI base or derived unit. The SI unit for area is the square meter (m²), and strictly speaking, large areas should be measured in square kilometers (km²).
However, the International Bureau of Weights and Measures (BIPM) explicitly lists the hectare as a non-SI unit accepted for use with the SI in the SI Brochure (9th edition, 2019). This recognition acknowledges the hectare's overwhelming global practical importance in agriculture, forestry, and land management.
In practice: Scientific papers, government statistics, and international organizations freely use hectares alongside SI units, and it is universally understood in metric contexts.
Why do some countries still use acres instead of hectares?
United States: Never fully metricated; acres are deeply embedded in property law, surveying, real estate, and agricultural tradition. US land is subdivided based on the Public Land Survey System (PLSS), which uses miles, chains, and acres.
United Kingdom: Officially metricated in 1995, but public resistance and tradition mean acres persist in real estate, rural communities, and casual speech. Government reports use hectares, but property listings often show both units.
Historical inertia: Countries that metricated recently (post-1970) often have older generations and established industries (especially real estate and agriculture) that resist change. The UK and Canada show gradual transitions, while the US shows little movement toward hectares.
Practical impact: Professionals working internationally (agriculture, forestry, climate science) routinely convert between acres and hectares, regardless of domestic preference.
How many hectares does it take to feed one person?
This depends on diet and farming intensity:
Vegetarian/low-meat diet (efficient):
- Intensive agriculture (e.g., modern wheat, rice): 0.15-0.20 ha per person
- Organic/lower-input farming: 0.25-0.35 ha per person
High-meat diet (less efficient due to feed conversion):
- Intensive agriculture: 0.35-0.50 ha per person
- Extensive/grassland-based: 0.50-1.00+ ha per person
Global average: Approximately 0.20-0.25 ha of arable land per person is needed to provide a balanced diet (2,500 kcal/day) with moderate meat consumption using modern farming practices.
Current reality: Global arable land per capita is about 0.19 ha per person (2025), down from ~0.38 ha in 1961 due to population growth. Higher yields per hectare have compensated, preventing widespread famine.
How do I measure the hectares of an irregular-shaped property?
Modern methods use GPS and GIS (Geographic Information Systems) to calculate areas of irregular parcels precisely:
Method 1: GPS boundary walk
- Walk or drive the perimeter with a GPS receiver
- Software calculates area from GPS coordinates
- Accuracy: ±0.5-2% depending on GPS quality
Method 2: Satellite imagery and GIS software
- Import satellite images or cadastral maps into GIS software (QGIS, ArcGIS, Google Earth Pro)
- Trace the boundary polygon
- Software calculates area in hectares
Method 3: Traditional surveying
- Professional land surveyor measures property using theodolite or total station
- Calculates area using coordinate geometry
- Accuracy: ±0.1% or better (legal surveys)
Method 4: Decomposition into simpler shapes
- Divide irregular property into rectangles, triangles, and trapezoids
- Measure each section's dimensions
- Calculate each area and sum them
Example: A property approximated as a large rectangle (300m × 200m = 60,000 m²) plus a triangular section (base 100m, height 50m = 2,500 m²) totals 62,500 m² = 6.25 hectares.
How many soccer fields fit in a hectare?
A standard FIFA soccer pitch has recommended dimensions of 105 meters × 68 meters = 7,140 m².
Calculation: 10,000 m² (1 ha) ÷ 7,140 m² (1 pitch) = 1.40 soccer fields per hectare
Or inversely: 1 soccer field ≈ 0.714 hectares
Note: FIFA allows pitch dimensions from 100-110m length and 64-75m width, so actual pitches vary from ~6,400 m² to ~8,250 m². The 105m × 68m size is the international standard recommendation.
Other comparisons:
- Rugby union pitch (max 100m × 70m): 0.70 ha, so ~1.43 per hectare
- American football field (with end zones, 109.7m × 48.8m): 0.535 ha, so ~1.87 per hectare
What is a "section" in acres and hectares?
A section is a unit of land area used in the United States Public Land Survey System (PLSS) and Canadian Dominion Land Survey (DLS).
Definition: 1 section = 1 square mile = 640 acres = 259 hectares (approximately 258.9988 ha precisely)
Sections divide townships (36 sections per township, each section 1 mile × 1 mile). US and Canadian rural land is often described in sections, half-sections (320 acres / 129.5 ha), or quarter-sections (160 acres / 64.75 ha).
Example: "I own the southwest quarter-section of Section 16" means 160 acres or about 64.75 hectares.
How many hectares is a typical golf course?
Golf course sizes vary widely depending on design, number of holes, and layout:
18-hole courses:
- Compact urban course: 40-50 hectares
- Standard parkland course: 50-70 hectares
- Championship course: 60-80 hectares
- Links course (with extensive dunes/rough): 70-100+ hectares
9-hole courses: 20-35 hectares
Example: Augusta National Golf Club (home of the Masters) is approximately 140 hectares (346 acres).
Comparison: An average 18-hole golf course (~60 ha) is about 24 times the size of a FIFA soccer field (0.714 ha), or roughly 0.6 km².
Conversion Table: Square Mile to Hectare
| Square Mile (mi²) | Hectare (ha) |
|---|---|
| 0.5 | 129.499 |
| 1 | 258.999 |
| 1.5 | 388.498 |
| 2 | 517.998 |
| 5 | 1,294.994 |
| 10 | 2,589.988 |
| 25 | 6,474.97 |
| 50 | 12,949.941 |
| 100 | 25,899.881 |
| 250 | 64,749.703 |
| 500 | 129,499.406 |
| 1,000 | 258,998.811 |
People Also Ask
How do I convert Square Mile to Hectare?
To convert Square Mile to Hectare, enter the value in Square Mile in the calculator above. The conversion will happen automatically. Use our free online converter for instant and accurate results. You can also visit our area converter page to convert between other units in this category.
Learn more →What is the conversion factor from Square Mile to Hectare?
The conversion factor depends on the specific relationship between Square Mile and Hectare. You can find the exact conversion formula and factor on this page. Our calculator handles all calculations automatically. See the conversion table above for common values.
Can I convert Hectare back to Square Mile?
Yes! You can easily convert Hectare back to Square Mile by using the swap button (⇌) in the calculator above, or by visiting our Hectare to Square Mile converter page. You can also explore other area conversions on our category page.
Learn more →What are common uses for Square Mile and Hectare?
Square Mile and Hectare are both standard units used in area measurements. They are commonly used in various applications including engineering, construction, cooking, and scientific research. Browse our area converter for more conversion options.
For more area conversion questions, visit our FAQ page or explore our conversion guides.
Helpful Conversion Guides
Learn more about unit conversion with our comprehensive guides:
All Area Conversions
Other Area Units and Conversions
Explore other area units and their conversion options:
- Square Meter (m²) • Square Mile to Square Meter
- Square Kilometer (km²) • Square Mile to Square Kilometer
- Square Centimeter (cm²) • Square Mile to Square Centimeter
- Square Millimeter (mm²) • Square Mile to Square Millimeter
- Square Inch (in²) • Square Mile to Square Inch
- Square Foot (ft²) • Square Mile to Square Foot
- Square Yard (yd²) • Square Mile to Square Yard
- Acre (acre) • Square Mile to Acre
Verified Against Authority Standards
All conversion formulas have been verified against international standards and authoritative sources to ensure maximum accuracy and reliability.
National Institute of Standards and Technology — Standards for area measurements
Last verified: December 3, 2025