Convert Milligrams to Grains
1 milligram is 0.02 gr. One milligram is exactly 0.0154323583529 grains.
One milligram is 0.015432358 grains. To convert milligrams to grains, multiply by 0.015432358; to go the other way, divide by 0.015432358 or multiply by 64.79891. The relation is exact but the figure is not: it is a rounding of a number that does not terminate, and it follows from NIST Handbook 44. One thousandth of a gram, and exactly 1,000 micrograms.
Factor checked against the defining standard · How we check
- Milligrams × 0.015432358
1 * 0.01543240.015 gr
1 milligram in every weight unit
| Unit | Value | Exact factor |
|---|---|---|
| ounces | 0.00003527396195 oz | × 0.0000352739619496 |
| pounds | 0.000002204622622 lb | × 0.00000220462262185 |
| stone | 0.0000001574730444 st | × 0.000000157473044418 |
| US tons | 0.000000001102311311 ton | × 0.00000000110231131092 |
| micrograms | 1,000 mcg | × 1,000 |
| milligrams (as entered) | 1 mg | — |
| centigrams | 0.1 cg | × 0.1 |
| grams | 0.001 g | × 0.001 |
| kilograms | 0.000001 kg | × 0.000001 |
| slugs | 0.00000006852176586 slug | × 0.0000000685217658568 |
| tonnes | 0.000000001 t | × 0.000000001 |
| carats | 0.005 ct | × 0.005 |
| troy ounces | 0.00003215074657 ozt | × 0.0000321507465686 |
| grains | 0.01543235835 gr | × 0.0154323583529 |
| long tons | 0.0000000009842065276 LT | × 0.000000000984206527611 |
Factors are entered by hand from NIST Handbook 44 rather than derived from a units library, so the ones that terminate are exact rather than rounded.
How do you convert milligrams to grains? The converter and the working
- 1.Take the measurement in milligrams.
- 2.Multiply by 0.015432358 — that is how many grains fit in one milligram.
- 3.To go back the other way, divide by 0.015432358, or multiply by 64.79891.
Worked example: 25 milligrams to grains
- Formula
- mg × 0.015432358 = gr
- Arithmetic
- 25 × 0.015432358 = 0.39 gr
- Answer
- 25 mg = 0.39 gr
The factor is rounded for display; the figure above is computed from the full value.
Milligrams to grains conversion table
| Milligrams | Grains |
|---|---|
| 1 mg | 0.02 gr |
| 2 mg | 0.03 gr |
| 3 mg | 0.05 gr |
| 4 mg | 0.06 gr |
| 5 mg | 0.08 gr |
| 6 mg | 0.09 gr |
| 7 mg | 0.11 gr |
| 8 mg | 0.12 gr |
| 9 mg | 0.14 gr |
| 10 mg | 0.15 gr |
| 12 mg | 0.19 gr |
| 15 mg | 0.23 gr |
| 20 mg | 0.31 gr |
| 25 mg | 0.39 gr |
| 50 mg | 0.77 gr |
| 100 mg | 1.54 gr |
| 200 mg | 3.09 gr |
| 300 mg | 4.63 gr |
| 500 mg | 7.72 gr |
| 1000 mg | 15.43 gr |
| 2000 mg | 30.86 gr |
| 5000 mg | 77.16 gr |
| 10000 mg | 154.32 gr |
What is a milligram?
One thousandth of a gram, and exactly 1,000 micrograms. The unit almost every medicine is dosed in.
What is a grain?
Exactly 64.79891 milligrams, the unit both the avoirdupois and troy systems are built from. Bullet weights and powder charges are still measured in it, and so are some pharmaceutical doses.
How many grains are in a milligram?
One milligram is 0.015432358 grains. Going the other way, one grain is 64.79891 milligrams. Both figures come from the same defined relation rather than from a measurement, which is why they are the same today as they were in 1959.
Every weight unit here
The whole group — 15 units with their symbols and the size of each one in kilograms — is on the conversion index, along with every pair it makes. The table above already gives each of them relative to a milligram.
Cite this page
- APA
- Rule Calculator. (2026). Convert Milligrams to grains. Rule Calculator. https://rulecalculators.com/convert/milligram-to-grain
- MLA
- "Convert Milligrams to grains." Rule Calculator, August 16, 2026, https://rulecalculators.com/convert/milligram-to-grain.
- Chicago
- Rule Calculator. "Convert Milligrams to grains." Rule Calculator. Last reviewed August 16, 2026. https://rulecalculators.com/convert/milligram-to-grain.
The date is when the figures on this page were last checked against their source, not the day you opened it. Add your own access date if your style needs one.
Questions people actually ask
- How many grains are in a milligram?
- 0.015432358. Exactly 64.79891 milligrams, the unit both the avoirdupois and troy systems are built from. Bullet weights and powder charges are still measured in it, and so are some pharmaceutical doses.
- How do I convert grains back to milligrams?
- Divide by 0.015432358, or multiply by 64.79891 — they are the same operation.
The values people look up
Each one is this page with the value filled in, and each answers in its own title.
Other weight conversions
Grains to milligrams — the same conversion the other way.