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Convert Grams to Milligrams

1 gram is 1,000 mg. One gram is exactly 1000 milligrams.

One gram is 1000 milligrams. To convert grams to milligrams, multiply by 1000; to go the other way, divide by 1000 or multiply by 0.001. The factor is exact rather than rounded: it follows from NIST Handbook 44. One thousandth of a kilogram, and the unit nutrition labels use worldwide.

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Milligrams
1,000 mg
Grams × 1000
value * 10001,000 mg

1 gram in every weight unit

UnitValueExact factor
ounces0.03527396195 oz× 0.0352739619496
pounds0.002204622622 lb× 0.00220462262185
stone0.0001574730444 st× 0.000157473044418
US tons0.000001102311311 ton× 0.00000110231131092
micrograms1,000,000 mcg× 1,000,000
milligrams1,000 mg× 1,000
grams (as entered)1 g
kilograms0.001 kg× 0.001
tonnes0.000001 t× 0.000001

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 grams to milligrams?

  1. 1.Take the measurement in grams.
  2. 2.Multiply by 1000 — that is how many milligrams fit in one gram.
  3. 3.To go back the other way, divide by 1000, or multiply by 0.001.

Grams to milligrams conversion table

GramsMilligrams
1 g1,000 mg
2 g2,000 mg
3 g3,000 mg
4 g4,000 mg
5 g5,000 mg
6 g6,000 mg
7 g7,000 mg
8 g8,000 mg
9 g9,000 mg
10 g10,000 mg
12 g12,000 mg
15 g15,000 mg
20 g20,000 mg
25 g25,000 mg
50 g50,000 mg
100 g100,000 mg

What are grams and milligrams?

Gram (g)
One thousandth of a kilogram, and the unit nutrition labels use worldwide.
Milligram (mg)
One thousandth of a gram, and exactly 1,000 micrograms. The unit almost every medicine is dosed in.

Source: NIST Handbook 44 — mass and weight

Questions people actually ask

How many milligrams are in a gram?
1000. One thousandth of a gram, and exactly 1,000 micrograms. The unit almost every medicine is dosed in.
How do I convert milligrams back to grams?
Divide by 1000, or multiply by 0.001 — they are the same operation.

Other weight conversions

Milligrams to grams — the same conversion the other way.

Calculators that work in weight