Milligram (mg)
One thousandth of a gram. Used for medicine doses and vitamins.
1 milligram = 0.000001 kilograms (exactly).
About the milligram
No single inventor can be credited with the milligram. It arrived with the metric system that France introduced in the 1790s, where the gram was the basic unit of mass and thousandths of it were named with a prefix. When the International System of Units was later built around the kilogram, the rule against stacked prefixes meant that a millionth of a kilogram is written 1 mg, never a microkilogram, so the milligram remained a gram-based unit even though the gram itself is not the SI base.
A milligram is small enough that doses of medicine and vitamins are measured in it routinely. A US penny weighs about 2.5 g, so a milligram is roughly one 2,500th of a coin. The unit is also at the center of a well-known safety problem: milligram and microgram differ by a factor of 1,000, and the abbreviation mcg for micrograms is used on prescriptions precisely so that a handwritten micro sign cannot be misread as milli. Confusing the two has caused serious medication errors.
Sources: Wikipedia: Milligram; Wikipedia: Microgram; Wikipedia: Gram
Milligram conversion chart
1 milligram expressed in every other weight & mass unit:
| Unit | 1 milligram |
|---|---|
| Kilograms | 0.000001 |
| Grams | 0.001 |
| Metric Tons | 1×10⁻⁹ |
| Pounds | 0.000002204622622 |
| Ounces | 0.00003527396195 |
| Micrograms | 1,000 |
| Carats | 0.005 |
| Stone | 1.574730444×10⁻⁷ |
| Short Tons | 1.102311311×10⁻⁹ |
| Long Tons | 9.842065276×10⁻¹⁰ |
| Troy Ounces | 0.00003215074657 |
| Daltons | 6.022140754×10²⁰ |
| Earth Masses | 1.674424835×10⁻³¹ |
| Solar Masses | 5.02899214×10⁻³⁷ |
| Quintals | 1×10⁻⁸ |
| Grains | 0.01543235835 |
| Drams | 0.0005643833912 |
| Hundredweight (US) | 2.204622622×10⁻⁸ |
| Hundredweight (UK) | 1.968413055×10⁻⁸ |
| Quarters (UK) | 7.873652221×10⁻⁸ |
| Slugs | 6.852176586×10⁻⁸ |
| Troy Pounds | 0.000002679228881 |
| Pennyweights | 0.0006430149314 |
| Scruples | 0.0007716179176 |
| Apothecaries' Drams | 0.0002572059725 |
| Roman Pounds | 0.000003040437823 |
| Roman Ounces | 0.00003649635036 |
| Attic Talents | 3.817376699×10⁻⁸ |
| Attic Minas | 0.000002290426019 |
| Attic Drachmas | 0.0002290426019 |
| Obols | 0.001374255612 |
| Shekels (biblical) | 0.00008695652174 |
| Hebrew Talents | 3.472222222×10⁻⁸ |
| Monme | 0.0002666666667 |
| Kin | 0.000001666666667 |
| Kan | 2.666666667×10⁻⁷ |
| Qian (Chinese) | 0.0002 |
| Liang (Chinese) | 0.00002 |
| Jin (Chinese) | 0.000002 |
| Dan (Chinese) | 2×10⁻⁸ |
| Catties (Hong Kong) | 0.000001653466966 |
| Taels (Hong Kong) | 0.00002645547146 |
| Tola | 0.00008573532418 |
| Seers | 0.000001071691552 |
| Maunds | 2.679228881×10⁻⁸ |
| Zolotniks | 0.0002344223996 |
| Funts | 0.000002441899996 |
| Poods | 6.104749989×10⁻⁸ |
| Libras (Castilian) | 0.000002173473624 |
| Arrobas (Spanish) | 8.693894495×10⁻⁸ |
| Arrobas (Brazilian) | 6.666666667×10⁻⁸ |
More Metric (SI) units
- kilogram (weight & mass)
- gram (weight & mass)
- microgram (weight & mass)
- metric ton (weight & mass)
- quintal (weight & mass)
- carat (weight & mass)
- meter (length)
- kilometer (length)
- centimeter (length)
- millimeter (length)
- micrometer (length)
- nanometer (length)
- picometer (length)
- decimeter (length)
- hectometer (length)
- decameter (length)
Browse all weight & mass units.