Troy Ounce to Milligram Converter
Convert troy ounces to milligrams with our free online weight converter.
Quick Answer
1 Troy Ounce = 31103.4768 milligrams
Formula: Troy Ounce × conversion factor = Milligram
Use the calculator below for instant, accurate conversions.
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Troy Ounce to Milligram Calculator
How to Use the Troy Ounce to Milligram Calculator:
- Enter the value you want to convert in the 'From' field (Troy Ounce).
- The converted value in Milligram will appear automatically in the 'To' field.
- Use the dropdown menus to select different units within the Weight category.
- Click the swap button (⇌) to reverse the conversion direction.
How to Convert Troy Ounce to Milligram: Step-by-Step Guide
Converting Troy Ounce to Milligram involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
1 Troy Ounce = 31103.5 milligramsExample Calculation:
Convert 5 troy ounces: 5 × 31103.5 = 155518 milligrams
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.
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View all Weight conversions →What is a Troy Ounce and a Milligram?
1 troy ounce = 31.1034768 grams (g) = 480 grains
The troy ounce (abbreviated "oz t", "ozt", or "t oz") is a unit of mass in the troy weight system, used exclusively for precious metals and gemstones. It differs significantly from the avoirdupois ounce used in everyday measurements.
Troy vs. Avoirdupois: Critical Distinction
| Unit | Grams | Use Cases | |----------|-----------|---------------| | Troy ounce | 31.1034768 g | Precious metals (gold, silver, platinum), gemstones, pharmaceuticals (historic) | | Avoirdupois ounce | 28.349523125 g | Food, body weight, general commerce | | Difference | +2.754 g (9.7% heavier) | Troy ounce is HEAVIER |
Critical for buyers: If someone sells you "1 ounce of gold" using avoirdupois ounces instead of troy ounces, you're getting 9.7% less metal than you paid for!
The Troy Weight System
Unlike the avoirdupois system (16 ounces = 1 pound), the troy system uses different ratios:
- 24 grains = 1 pennyweight (dwt)
- 20 pennyweights = 1 troy ounce (oz t)
- 12 troy ounces = 1 troy pound (lb t)
Paradox: The troy ounce is heavier than the avoirdupois ounce, BUT the troy pound (373.24 g) is lighter than the avoirdupois pound (453.59 g) because it contains only 12 ounces instead of 16!
Why Troy Ounces Persist
Despite global metrication, troy ounces remain dominant in precious metals for these reasons:
- Market convention: Centuries of gold/silver trading established price benchmarks in troy ounces
- Legal tender: U.S. Mint, Royal Canadian Mint, and others mint official coins in troy ounce denominations
- Futures contracts: COMEX gold contracts specify 100 troy ounces per contract
- LBMA standards: London Bullion Market Association requires troy ounce quotations
- Central banks: Gold reserves reported in troy ounces (e.g., Fort Knox holds 147.3 million oz t)
The milligram (mg) is a unit of mass in the metric system equal to one-thousandth of a gram (1/1,000 g) or one-millionth of a kilogram (1/1,000,000 kg). It represents an extremely small quantity of mass, making it the preferred unit for measuring precise amounts of medications, nutrients, chemicals, and other substances where accuracy is paramount.
The milligram is part of the International System of Units (SI) and serves as a critical measurement standard in medicine, pharmacology, chemistry, nutrition science, and precision manufacturing. Its small scale allows for expressing tiny quantities without resorting to decimal fractions of grams, providing clarity and reducing the risk of measurement errors that could have serious consequences in medical and scientific applications.
Note: The Troy Ounce is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Milligram belongs to the metric (SI) system.
History of the Troy Ounce and Milligram
Ancient and Medieval Origins (Pre-1500)
The word "ounce" derives from the Latin "uncia" (one-twelfth), reflecting the Roman system where 1 uncia = 1/12 of a libra (pound). The troy system's specific origins trace to Troyes, France, a major European trade city.
12th-15th centuries - Champagne Fairs: Troyes hosted international trade fairs where merchants from Italy, Flanders, England, and German states exchanged goods. Precious metals, spices, and textiles required standardized weights. The "Troyes weight" system emerged as a trusted standard for valuable commodities, particularly gold, silver, and gemstones.
Why "troy" not "avoirdupois"? Two parallel weight systems developed:
- Troy weights: For precious metals, spices, medicines (high-value, small quantities)
- Avoirdupois weights: For bulk goods like wool, grain, iron (from French "avoir de pois" = goods of weight)
English Standardization (1500-1800)
1527 - King Henry VIII standardization: Henry VIII officially defined troy weights for the English realm, establishing:
- 1 troy pound = 5,760 grains
- 1 troy ounce = 480 grains
- 1 grain = 64.79891 milligrams (based on barley grain weight)
1758 - British assay offices: The Goldsmiths' Company and assay offices in London, Birmingham, Sheffield, and Edinburgh used troy ounces exclusively for hallmarking gold and silver items. This reinforced troy ounces as the legal standard for precious metals in British commerce.
The Tower Pound obsolescence: England previously used the "Tower pound" for minting coins (5,400 grains), but troy weights (5,760 grains per pound) eventually replaced it in 1527, creating unified standards for bullion and coinage.
American Adoption (1776-1900)
1776-1792 - Early United States: American colonies inherited British troy standards. The early U.S. used Spanish silver dollars and British gold sovereigns, all measured in troy ounces.
1828 - U.S. Coinage Act: Congress officially adopted troy weights for all U.S. coinage. The Act specified:
- Gold dollar = 25.8 grains (1.672 g) of 90% gold
- Silver dollar = 412.5 grains (26.73 g) of 90% silver
- All coins measured in troy grains
1849-1855 - California Gold Rush: The discovery of gold at Sutter's Mill created massive demand for standardized weights. Assay offices in San Francisco weighed gold dust and nuggets in troy ounces, establishing the unit in the American West.
1873 - Coinage Act ("Crime of 1873"): This act demonetized silver, ending bimetallism. However, troy ounces remained the standard for measuring both gold and silver bullion.
Global Standardization (1900-Present)
1900-1971 - The Gold Standard era: Most nations tied currencies to gold reserves, measured in troy ounces:
- 1900: Gold Standard Act (U.S. fixed $20.67 per troy ounce)
- 1933: FDR revalued gold to $35 per troy ounce
- 1944: Bretton Woods Agreement ($35/oz t peg)
- 1971: Nixon ended gold convertibility, but troy ounce pricing persisted
1919 - London Bullion Market Association (LBMA): Founded to standardize London gold market practices. LBMA established:
- Good Delivery bars: 350-430 troy ounces (typically 400 oz t)
- Minimum purity: 995 parts per 1,000 (99.5% pure gold)
- Troy ounce quotations for spot prices
1974 - COMEX gold futures: The Commodity Exchange (COMEX) in New York launched gold futures contracts:
- Contract size: 100 troy ounces
- Delivery specifications: 1 kg bars (32.1507 oz t) or 100 oz bars
- Global price discovery mechanism
1975 - Gold ownership legalization: U.S. citizens regained the right to own gold bullion (banned since 1933). Investment coins like the Krugerrand (1 oz t), Canadian Maple Leaf (1 oz t), and American Gold Eagle (1 oz t) popularized troy ounce denominations for retail investors.
2000s-Present - Digital age: Despite metrication, troy ounces dominate:
- ETFs: SPDR Gold Shares (GLD) holds 900+ tons (28.9M oz t)
- Central banks: Reserve holdings reported in troy ounces (U.S. 261.5M oz t, Germany 108.9M oz t)
- Spot prices: Bloomberg, Reuters, Kitco quote gold/silver per troy ounce
- Refineries: Swiss refiners (PAMP, Valcambi) produce bars in troy ounce sizes
Cultural Significance
The troy ounce represents continuity in global finance—a medieval trade standard that survived the industrial revolution, world wars, and digital transformation. While most historical units vanished with metrication, the troy ounce persists because precious metals markets value tradition, legal precedent, and universal standardization over decimal convenience.
The milligram emerged as a practical subdivision of the gram when the metric system was formalized in France in the late 18th century. While the kilogram was established as the base unit of mass in 1795, scientists and physicians quickly recognized the need for much smaller units to measure chemicals, medicines, and biological samples.
The term "milligram" combines the Latin prefix "milli-" (meaning one-thousandth) with "gram," creating a logical decimal relationship that simplified calculations and conversions. This standardization was revolutionary—before the metric system, apothecaries used confusing units like grains, scruples, and drams, which varied by region and led to dangerous medication errors.
The importance of the milligram grew dramatically during the 19th century as pharmaceutical science advanced. The ability to precisely measure active ingredients in medications became critical for patient safety. By the early 20th century, the milligram had become the global standard for drug dosing, appearing on prescription labels, medication packaging, and medical literature worldwide.
The 1960 formalization of the International System of Units (SI) cemented the milligram's status as an official metric unit, though it's technically a submultiple of the kilogram rather than a base unit itself. Today, the milligram remains indispensable in healthcare, with virtually every pharmaceutical product worldwide labeled in milligrams.
Common Uses and Applications: troy ounces vs milligrams
Explore the typical applications for both Troy Ounce (imperial/US) and Milligram (metric) to understand their common contexts.
Common Uses for troy ounces
1. Precious Metals Trading
The troy ounce is the universal standard for global bullion markets:
Spot price quotations:
- Gold: $1,800-2,100 per troy ounce (fluctuates with markets)
- Silver: $20-30 per oz t
- Platinum: $900-1,200 per oz t
- Palladium: $1,000-1,600 per oz t
- Rhodium: $3,000-15,000 per oz t (highest volatility)
Major markets:
- London Bullion Market (LBMA): Sets gold/silver fix twice daily in troy ounces
- COMEX (New York): Futures contracts (100 oz t gold, 5,000 oz t silver)
- Shanghai Gold Exchange: Trades gold in grams but converts to oz t for international quotes
- Dubai Gold Souk: Retail sales in grams, wholesale in troy ounces
Why troy ounces persist: Centuries of price history, legal contracts, and central bank reserves create network effects—changing to grams would require recalibrating trillions in financial instruments.
2. Investment Coins & Bars
Government minted coins (1 oz troy):
- American Gold Eagle: Most popular U.S. bullion coin, 22K gold
- Canadian Maple Leaf: 24K gold (.9999 fine), iconic design
- South African Krugerrand: First modern bullion coin (1967)
- Austrian Philharmonic: European alternative, euro-denominated
- Chinese Gold Panda: Annual design changes, collector value
Fractional coins:
- 1/2 oz, 1/4 oz, 1/10 oz troy ounce denominations
- Higher premiums per ounce (manufacturing costs)
- Easier to liquidate small amounts
Private mint bars:
- 1 oz, 10 oz, 100 oz troy ounce sizes (silver)
- 1 oz, 10 oz, 1 kg gold bars
- Lower premiums than coins (no numismatic value)
- Stackability for storage
3. Jewelry Manufacturing
Jewelers purchase gold in troy ounces but often work in grams or pennyweights (dwt):
Pricing structure:
- Spot price: Current troy ounce price (e.g., $2,000/oz)
- Karat adjustment: 14K = 58.3%, 18K = 75%, 22K = 91.67%
- Fabrication cost: Labor, design, gemstones
- Retail markup: 2-3× material cost
Example calculation (14K ring):
- Weight: 5 grams = 0.16075 oz t
- Pure gold: 0.16075 × 0.583 = 0.0938 oz t
- Gold value: 0.0938 × $2,000 = $187.60
- Retail price: $500-800 (includes labor, overhead, profit)
Scrap gold recycling: Jewelers sell scrap in troy ounces to refineries, receiving 90-95% of spot price (refining losses, processing fees).
4. Pharmaceutical & Apothecary (Historic)
Before metrication, pharmacists used troy weights for compounding:
Apothecaries' system:
- 20 grains = 1 scruple
- 3 scruples = 1 dram
- 8 drams = 1 troy ounce
Modern legacy:
- Grain measurements persist (aspirin: 5 grains = 325 mg)
- Troy ounces phased out in medicine by 1970s
- Replaced by milligrams and grams for precision
5. Mining & Geology
Gold production and ore grades measured in troy ounces:
Reserve reporting:
- Gold deposits: "10 million oz t at 2 g/t grade" (metric tons ore, troy ounces gold)
- Production rates: "500,000 oz t per year" (annual mine output)
Ore grades:
- High-grade: 10-20 g/t (0.32-0.64 oz t per metric ton ore)
- Low-grade: 1-5 g/t (0.032-0.16 oz t/t)
- Ultra-low-grade: 0.5 g/t (economical with modern extraction)
Example (Nevada Gold Mine):
- Reserves: 50 million metric tons
- Grade: 2 g/t (0.064 oz t/t)
- Contained gold: 3.2 million troy ounces
- Mine life: 15 years (213,000 oz t/year production)
6. Central Banking & Reserves
Countries hold gold reserves measured in troy ounces:
Reserve valuation: Most central banks value gold at historic cost ($42.22/oz t, a 1973 price), not market rates. However, market value uses current spot prices:
- U.S. reserves: 261.5M oz t × $2,000 = $523 billion market value
- Official books: 261.5M oz t × $42.22 = $11 billion (!)
Reserve diversification:
- Gold as % of reserves: U.S. (70%), Germany (67%), Italy (64%)
- Rationale: Inflation hedge, currency crisis protection, geopolitical insurance
7. Collectibles & Numismatics
Coin collectors distinguish between bullion value (troy ounces) and numismatic value (rarity, condition):
Example: 1933 Double Eagle
- Gold content: 0.9675 oz t (~$1,935 melt value)
- Auction price: $18.9 million (2021 Sotheby's)
- Numismatic premium: 9,700× bullion value!
Modern bullion vs. collectible:
- Bullion: Trades at spot + 3-10% premium (1 oz Gold Eagle)
- Collectible: Rare dates, low mintages command 2-100× premiums
When to Use milligrams
The milligram is essential across multiple fields:
Pharmaceuticals & Medicine:
- Prescription medication dosing and labeling
- Over-the-counter drug formulations
- Injectable medication concentrations (mg/mL)
- Pediatric dosing (often calculated as mg per kg of body weight)
- Hormone replacement therapy dosing
Nutrition & Food Science:
- Vitamin and mineral content on nutrition labels
- Dietary supplement formulations
- Sodium, cholesterol, and nutrient tracking
- Food additive regulations and limits
- Daily recommended intake guidelines
Scientific Research:
- Chemical synthesis and reagent measurement
- Biological sample preparation
- Environmental testing (pollutants, contaminants)
- Pharmaceutical research and development
- Quality control testing
Analytical Chemistry:
- Trace element analysis
- Drug testing and toxicology
- Water quality testing
- Soil sample analysis
- Forensic investigations
Precision Manufacturing:
- Microelectronics component specifications
- Fine powder measurements
- Catalyst preparation
- Cosmetics formulation
- Flavoring and fragrance compounds
Additional Unit Information
About Troy Ounce (oz t)
1. Is a troy ounce the same as a regular ounce?
No. The troy ounce (31.1035 g) is about 9.7% heavier than the avoirdupois ounce (28.3495 g) used for food and general items.
Visual comparison:
- 1 troy ounce gold = Size of a large grape (but very dense)
- 1 avoirdupois ounce flour = Same volume but less mass
When it matters: Precious metals (gold, silver, platinum) always use troy ounces. If someone offers you "1 ounce of gold" at a suspiciously low price, verify it's troy ounces—not avoirdupois!
2. How many grams are in a troy ounce?
Exactly 31.1034768 grams.
This precise definition comes from the 1959 international agreement on units. It's the same globally—LBMA (London), COMEX (New York), and Shanghai Gold Exchange all use this exact conversion.
For practical purposes:
- 1 troy oz ≈ 31.1 grams (rounded)
- 10 troy oz ≈ 311 grams
- 32.15 troy oz = 1 kilogram (exactly 1,000 g)
3. How many troy ounces are in a troy pound?
12 troy ounces = 1 troy pound (373.24 grams).
This differs from the avoirdupois system where 16 ounces = 1 pound. The troy system uses base-12 (duodecimal), a remnant of Roman and medieval counting systems.
Paradox explained:
- Troy ounce (31.10 g) > Avoirdupois ounce (28.35 g)
- BUT Troy pound (373.24 g) < Avoirdupois pound (453.59 g)
Why: 12 × 31.10 = 373.24, while 16 × 28.35 = 453.59.
4. Why do precious metals use troy ounces instead of grams?
Historical inertia and market convention.
Reasons troy ounces persist:
-
Centuries of price data: Gold has been priced per troy ounce since the 1700s. Changing would break historical charts and analysis.
-
Legal tender and contracts: U.S. Mint, Canadian Mint, and others legally define coins in troy ounces. Futures contracts, options, and derivatives are denominated in oz t.
-
Central bank reserves: Fort Knox holds "147.3 million troy ounces," not "4,582.7 metric tons"—the legal records use troy ounces.
-
Network effects: If London uses oz t, New York must too. Shanghai converts grams to oz t for international quotes.
-
Cultural identity: "An ounce of gold" evokes tangibility. "31.1 grams of gold" lacks the same resonance.
Metrication attempts failed: France and other metric-first countries tried quoting gold in grams, but international traders kept converting back to oz t for comparison.
5. How much is 1 troy ounce of gold worth?
It fluctuates constantly. As of 2024, gold trades between $1,800 - $2,100 per troy ounce, depending on economic conditions.
Price drivers:
- Inflation fears: Gold rises when currency value erodes
- Interest rates: Low rates → gold attractive (no yield anyway)
- Geopolitical crises: Wars, sanctions boost safe-haven demand
- Central bank buying: China, Russia, Turkey accumulating reserves
- Jewelry demand: India, China seasonal festivals
Historical context:
- 1900: $20.67/oz (Gold Standard Act)
- 1971: $35/oz (Nixon Shock, end of Bretton Woods)
- 1980: $850/oz (Hunt Brothers silver crisis, inflation)
- 2011: $1,900/oz (Financial crisis aftermath)
- 2020: $2,067/oz (COVID-19 pandemic peak)
Real-time prices: Check Bloomberg, Reuters, Kitco, or bullion dealer sites.
6. What's the difference between "carat" and "karat"?
Completely different units—one measures weight, the other purity:
CARAT (ct) = Gemstone weight
- 1 carat = 200 milligrams = 0.00643 troy ounces
- Measures diamonds, rubies, sapphires, emeralds
- "5-carat diamond" = 1 gram weight
KARAT (K or kt) = Gold purity
- 24K = 100% pure gold
- 18K = 75% gold (18/24)
- 14K = 58.3% gold (14/24)
- Measures alloy composition, not weight
Example: "18K gold ring weighing 0.2 troy ounces" means:
- Karat: 75% pure (18/24)
- Weight: 0.2 oz t = 6.22 g total
- Pure gold: 0.15 oz t = 4.67 g (6.22 × 0.75)
7. Can I buy fractional troy ounces?
Yes! Governments and private mints produce fractional coins:
Common sizes:
- 1/10 oz t (3.11 g) — Popular for small investors
- 1/4 oz t (7.78 g)
- 1/2 oz t (15.55 g)
- 1 oz t (31.10 g) — Most popular size
Trade-offs:
- Pros: Lower entry cost ($200 for 1/10 oz vs. $2,000 for 1 oz), easier to liquidate small amounts
- Cons: Higher premiums per ounce (1/10 oz costs ~15% premium vs. 3-5% for 1 oz)
Example:
- 1 oz Gold Eagle: $2,050 ($50 premium over $2,000 spot = 2.5%)
- 1/10 oz Gold Eagle: $240 ($40 premium over $200 spot = 20%!)
Why higher premiums? Minting costs don't scale linearly. Striking a 1/10 oz coin costs almost as much as a 1 oz coin, so the percentage premium is higher.
8. What is a "Good Delivery" gold bar?
The international standard for large-scale gold bullion, set by the London Bullion Market Association (LBMA).
Specifications:
- Weight: 350-430 troy ounces (typically 400 oz t = 12.4 kg)
- Purity: Minimum 995 parts per 1,000 (99.5% pure gold)
- Fineness stamp: Refinery mark, serial number, purity, year
- Refiners: LBMA-approved list (~70 refineries: PAMP, Valcambi, Rand, Johnson Matthey)
Why "Good Delivery"? Before standardization, banks had to assay every bar (costly, time-consuming). LBMA Good Delivery certification means bars are universally accepted without re-assaying.
Where they're used:
- Central bank reserves (Fort Knox, Bank of England vaults)
- Commercial bank vaults (HSBC, JPMorgan)
- ETF backing (SPDR Gold Shares stores Good Delivery bars)
Retail availability: Most investors never see Good Delivery bars—they're institutional. Retail investors buy 1 oz coins or small bars (1 oz, 10 oz, 100 oz).
9. How do I convert troy ounces to kilograms?
Formula:
1 troy ounce = 0.0311034768 kilograms
OR
1 kilogram = 32.1507466 troy ounces
Quick method: Divide troy ounces by 32.15 to get kilograms:
400 oz t ÷ 32.15 ≈ 12.44 kg
Precise method: Multiply troy ounces by 0.0311034768:
400 oz t × 0.0311034768 = 12.44139072 kg (EXACT)
Common conversions:
- 1 oz t = 0.0311 kg
- 10 oz t = 0.311 kg
- 100 oz t = 3.11 kg
- 1,000 oz t = 31.1 kg
- 32.15 oz t = 1 kg (exactly 1,000 g)
10. What's the smallest amount of gold I can buy?
Technically, you can buy any amount, but practical minimums exist:
Physical gold:
- Smallest coins: 1/10 oz t (~$200-250)
- Gold jewelry: Varies, but 14K chains start around $100-200 (contains ~0.05 oz t pure gold)
- Gold leaf: Decorative, negligible weight (~0.001 oz t per sheet)
Paper gold (no physical delivery):
- Gold ETFs (GLD, IAU): 1 share ≈ 0.1 oz t (~$200)
- Fractional platforms (OneGold, Vaulted): Buy as little as $1 worth (0.0005 oz t)
- Futures contracts: 100 oz t minimum (~$200,000—professional traders only)
Recommendation for beginners: Start with 1/4 oz or 1/2 oz coins (balance between affordability and premiums). Avoid tiny fractions (1/20 oz) due to extremely high premiums.
11. How do jewelers measure gold?
Three units, depending on context:
- Troy ounces (oz t): Buying gold from refineries, calculating melt value
- Pennyweights (dwt): Traditional unit (1 oz t = 20 dwt, 1 dwt = 1.555 g)
- Grams (g): Modern standard, easier math
Example (jeweler selling 14K scrap):
- Weighs scrap: 25.5 grams
- Converts to troy ounces: 25.5 ÷ 31.1 = 0.82 oz t
- Calculates pure gold: 0.82 × 0.583 (14K) = 0.478 oz t
- Refinery pays: 0.478 × $2,000 × 0.95 = $908 (95% of spot, 5% refining fee)
Pennyweight legacy: Older jewelers still use "dwt" for historic reasons. Most modern shops use grams for precision.
12. Why are central banks buying more gold?
Diversification away from the U.S. dollar and geopolitical hedging.
Key drivers:
- De-dollarization: Russia, China, Turkey reducing USD reserves after sanctions
- Inflation hedge: 2020-2024 inflation spikes drove safe-haven demand
- Currency debasement fears: Massive money printing (COVID stimulus) erodes fiat value
- Geopolitical tensions: Ukraine war, Taiwan tensions increase reserve gold holdings
Recent trends (2020-2024):
- China: Added 300+ tons (9.6M oz t) in 2023 alone
- Russia: Doubled reserves to 2,300 tons (74M oz t) before Ukraine war
- Poland: Increased from 103 to 228 tons (7.3M oz t)
- Singapore: Tripled reserves to 230 tons (7.4M oz t)
Why troy ounces matter: Central bank transactions are reported in troy ounces (IMF, World Gold Council standards), even though storage is often measured in metric tons.
About Milligram (mg)
How many milligrams are in a gram?
There are exactly 1,000 milligrams (mg) in one gram (g). This is a defined relationship in the metric system. The prefix "milli-" always means one-thousandth, so a milligram is one-thousandth of a gram.
To convert:
- Grams to milligrams: multiply by 1,000
- Milligrams to grams: divide by 1,000
Example: 3.5 g = 3,500 mg
How many milligrams are in a kilogram?
There are 1,000,000 (one million) milligrams in one kilogram. Since 1 kg = 1,000 g and 1 g = 1,000 mg, we multiply: 1,000 × 1,000 = 1,000,000 mg.
This large conversion factor is why kilograms are never used for medications—the numbers would be unwieldy. A 500 mg tablet would be "0.0005 kg," which is impractical and error-prone.
Convert milligrams to kilograms →
Is a milligram the same as a microgram?
No! A milligram (mg) is 1,000 times larger than a microgram (mcg or μg). This is one of the most dangerous medication errors in healthcare.
- 1 milligram (mg) = 1,000 micrograms (mcg)
- 1 microgram (mcg) = 0.001 milligrams (mg)
Some medications like levothyroxine, folic acid, and vitamin B12 are dosed in micrograms because the active doses are extremely small. Always verify which unit is intended, as confusing them can cause a 1,000-fold overdose or underdose.
Convert micrograms to milligrams →
What does "mg" stand for?
"mg" is the internationally recognized abbreviation for milligram. The "m" represents the metric prefix "milli-" (meaning 1/1,000), and "g" stands for gram. Together, "mg" means one-thousandth of a gram.
This abbreviation is standardized worldwide by the International System of Units (SI) and is understood across all languages and countries. Never use "mgs" with an "s"—the plural of "mg" is still "mg" (e.g., "500 mg," not "500 mgs").
How much does a milligram weigh in everyday terms?
A milligram is extremely light—almost imperceptible to human senses:
- 1 mg ≈ weight of a very small grain of sand
- 10 mg ≈ weight of a small feather fiber
- 100 mg ≈ weight of a single drop of water
- 1,000 mg = 1 gram = weight of a small paperclip
For comparison, a U.S. dollar bill weighs about 1 gram (1,000 mg), so 1 mg is 1/1,000th the weight of a dollar bill. Most household scales cannot accurately measure milligrams—you need a laboratory analytical balance.
Are milligrams used for measuring liquids?
Milligrams measure mass (weight), not volume. However, liquid medications are often prescribed in milligrams of the active ingredient, then measured in milliliters (mL) based on the concentration.
Example: A prescription might call for "500 mg of amoxicillin." If the bottle says "250 mg/5 mL," you'd measure 10 mL of the liquid to get 500 mg of the drug.
The key is understanding concentration: mg/mL tells you how many milligrams of active ingredient are in each milliliter of liquid.
Learn about medication concentrations →
How do I convert milligrams to ounces or pounds?
For converting between metric (mg) and imperial (oz, lb) units:
Milligrams to ounces:
- 1 ounce = 28,349.5 mg
- To convert mg to oz: divide mg by 28,349.5
Example: 50,000 mg ÷ 28,349.5 = 1.76 oz
Milligrams to pounds:
- 1 pound = 453,592 mg
- To convert mg to lb: divide mg by 453,592
Example: 100,000 mg ÷ 453,592 = 0.22 lb
These conversions are rarely used for medications (which stay in mg) but appear in industrial, commercial, or international shipping contexts.
Convert milligrams to ounces → Convert milligrams to pounds →
What is the difference between mass and weight when measuring milligrams?
Technically, mass is the amount of matter in an object (measured in mg, g, kg), while weight is the force of gravity on that mass. In everyday use and in medicine, these terms are used interchangeably, and we say "weight" when we mean "mass."
For practical purposes at Earth's surface, the distinction doesn't matter. A 500 mg tablet has 500 mg of mass and "weighs" 500 mg. The only time it matters is in scientific contexts involving gravity variations (like space) or high-precision physics experiments.
In medicine, pharmacy, and nutrition, "milligrams" always refers to mass, which is constant regardless of location or gravity.
Can I measure milligrams accurately at home?
Measuring true milligrams at home is challenging because most household scales lack sufficient precision:
Typical household scales:
- Kitchen scales: accurate to ±1-5 grams (not useful for mg)
- Food scales: accurate to ±0.1 grams = ±100 mg (limited use)
- Jewelry/pocket scales: accurate to ±0.01 g = ±10 mg (better, but still limited)
What you need for accurate mg measurements:
- Laboratory analytical balance: accurate to ±1 mg or ±0.1 mg
- Cost: $200-$2,000+ depending on precision
- Environment: Requires stable surface, no air currents, calibrated regularly
For medications: Never attempt to divide, measure, or adjust milligram doses at home without consulting a healthcare provider. Use pre-measured doses from pharmacies, and use provided measuring devices (syringes, droppers, cups) that are calibrated for the specific medication.
Learn about weight measurement tools →
Why are medications measured in milligrams instead of grams?
Milligrams are the standard for medications because most therapeutic doses fall conveniently between 1 mg and 1,000 mg, making the numbers practical to read and write without decimals:
- Easier to read: "500 mg" is clearer than "0.5 g"
- Reduces decimal errors: Writing "250 mg" prevents mistakes from misplaced decimal points in "0.250 g"
- International standard: The entire global pharmaceutical industry uses mg, ensuring consistency
- Appropriate scale: Most drug doses require precision at the milligram level
For very potent drugs requiring smaller amounts, micrograms (mcg) are used instead. For substances requiring larger amounts (like some electrolyte solutions), grams are used.
Convert between medication units →
How do milligrams relate to "mg/kg" dosing in medicine?
Many medications are dosed based on body weight using mg/kg (milligrams per kilogram). This adjusts the dose proportionally to patient size, which is especially important for children, neonates, and certain drugs with narrow therapeutic windows.
How it works:
- Patient weight is measured in kilograms
- Prescribed dose is given as mg/kg (e.g., "5 mg/kg")
- Total dose = weight (kg) × dose (mg/kg)
Example:
- Patient weighs 60 kg
- Drug dose: 10 mg/kg
- Total dose: 60 kg × 10 mg/kg = 600 mg
This ensures safe, effective dosing regardless of whether the patient is a 3 kg newborn or a 100 kg adult.
Conversion Table: Troy Ounce to Milligram
| Troy Ounce (oz t) | Milligram (mg) |
|---|---|
| 0.5 | 15,551.738 |
| 1 | 31,103.477 |
| 1.5 | 46,655.215 |
| 2 | 62,206.954 |
| 5 | 155,517.384 |
| 10 | 311,034.768 |
| 25 | 777,586.92 |
| 50 | 1,555,173.84 |
| 100 | 3,110,347.68 |
| 250 | 7,775,869.2 |
| 500 | 15,551,738.4 |
| 1,000 | 31,103,476.8 |
People Also Ask
How do I convert Troy Ounce to Milligram?
To convert Troy Ounce to Milligram, enter the value in Troy Ounce in the calculator above. The conversion will happen automatically. Use our free online converter for instant and accurate results. You can also visit our weight converter page to convert between other units in this category.
Learn more →What is the conversion factor from Troy Ounce to Milligram?
The conversion factor depends on the specific relationship between Troy Ounce and Milligram. 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 Milligram back to Troy Ounce?
Yes! You can easily convert Milligram back to Troy Ounce by using the swap button (⇌) in the calculator above, or by visiting our Milligram to Troy Ounce converter page. You can also explore other weight conversions on our category page.
Learn more →What are common uses for Troy Ounce and Milligram?
Troy Ounce and Milligram are both standard units used in weight measurements. They are commonly used in various applications including engineering, construction, cooking, and scientific research. Browse our weight converter for more conversion options.
For more weight conversion questions, visit our FAQ page or explore our conversion guides.
Helpful Conversion Guides
Learn more about unit conversion with our comprehensive guides:
📚 How to Convert Units
Step-by-step guide to unit conversion with practical examples.
🔢 Conversion Formulas
Essential formulas for weight and other conversions.
⚖️ Metric vs Imperial
Understand the differences between measurement systems.
⚠️ Common Mistakes
Learn about frequent errors and how to avoid them.
All Weight Conversions
Other Weight Units and Conversions
Explore other weight units and their conversion options:
- Kilogram (kg) • Troy Ounce to Kilogram
- Gram (g) • Troy Ounce to Gram
- Pound (lb) • Troy Ounce to Pound
- Ounce (oz) • Troy Ounce to Ounce
- Stone (st) • Troy Ounce to Stone
- Ton (metric) (t) • Troy Ounce to Ton (metric)
- Ton (US) (ton) • Troy Ounce to Ton (US)
- Ton (UK) (long ton) • Troy Ounce to Ton (UK)
- Microgram (µg) • Troy Ounce to Microgram
- Carat (ct) • Troy Ounce to Carat
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 — US standards for weight and mass measurements
International Organization for Standardization — International standard for mechanics quantities
Last verified: December 3, 2025