Grains to Milligrams (gr to mg) Converter

How to convert grains to milligrams

Formulamg = gr × 64.79891

Multiply the value in grains by 64.79891. To go the other way, multiply by 0.01543235835 (or divide by 64.79891).

A grain is larger than a milligram: one grain contains 64.79891 milligrams.

Worked examples

1 grain1 gr × 64.79891 = 64.79891 mg
5 grains5 gr × 64.79891 = 323.99455 mg
10 grains10 gr × 64.79891 = 647.9891 mg
20 grains20 gr × 64.79891 = 1,295.9782 mg
100 grains100 gr × 64.79891 = 6,479.891 mg

Grains to milligrams conversion table

Values are calculated by the conversion engine and rounded to 8 significant figures.

Grains to milligrams: 0.1–10 gr
Grains (gr)	Milligrams (mg)
0.1 gr	6.479891 mg
0.25 gr	16.199728 mg
0.5 gr	32.399455 mg
1 gr	64.79891 mg
2 gr	129.59782 mg
3 gr	194.39673 mg
4 gr	259.19564 mg
5 gr	323.99455 mg
6 gr	388.79346 mg
7 gr	453.59237 mg
8 gr	518.39128 mg
9 gr	583.19019 mg
10 gr	647.9891 mg

Grains to milligrams: 12–1,000 gr
Grains (gr)	Milligrams (mg)
12 gr	777.58692 mg
15 gr	971.98365 mg
20 gr	1,295.9782 mg
25 gr	1,619.9728 mg
30 gr	1,943.9673 mg
40 gr	2,591.9564 mg
50 gr	3,239.9455 mg
75 gr	4,859.9183 mg
100 gr	6,479.891 mg
250 gr	16,199.728 mg
500 gr	32,399.455 mg
1,000 gr	64,798.91 mg

About the units

Grain (gr)

Exactly 64.79891 mg; 7,000 grains make a pound. Used for bullets, arrows and some medicines. One grain equals 0.00006479891 kilograms (kg).

Milligram (mg)

One thousandth of a gram. Medication doses and vitamin contents are usually given in milligrams. One milligram equals 0.000001 kilograms (kg).

Frequently asked questions

How many milligrams are in one grain?

There are 64.79891 milligrams in one grain, and this value is exact by definition.

How do I convert grains to milligrams?

Multiply the number of grains by 64.79891. For example, 10 gr × 64.79891 = 647.9891 mg.

How many grains are in one milligram?

One milligram equals 0.01543235835 grains. That is the reverse factor, 1 ÷ 64.79891.

What is 10 grains in milligrams?

10 gr = 647.9891 mg.

Is this gr to mg converter accurate?

Yes. Both units are defined exactly in terms of SI units, so the conversion factor is exact; results are shown to 12 significant figures by default and you can change precision in the converter. Calculations run in your browser using the same tested engine that generated this page.

Grains to Milligrams Converter