HomeUnit Conversion › Grams to Milligrams

Grams to Milligrams (g to mg)

Convert grams to milligrams: 1 g = 1000 mg. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.

Formula

1 g = 1000 mg

milligrams = grams × 1000 — reverse: grams = milligrams × 0.001

The factor is derived from the SI definitions of both units (base unit: kg) as listed in NIST SP 811; results on this page are shown to 6 significant figures, the API returns up to 12.

Worked examples

Grams to milligrams conversion table

Grams (g)Milligrams (mg)
11000
22000
33000
44000
55000
66000
77000
88000
99000
1010000
1515000
2020000
2525000
3030000
4040000
5050000
7575000
100100000
200200000
250250000
500500000
10001000000

FAQ

How many milligrams are in one gram?

1 g = 1000 mg. The factor comes from the SI definitions of both units (NIST SP 811 / BIPM), so it is exact or correct to at least 10 significant figures.

What is the formula to convert grams to milligrams?

Multiply the value in grams by 1000: milligrams = grams × 1000. For example, 5 g = 5000 mg.

How do I convert milligrams back to grams?

Multiply by the inverse factor 0.001 (grams = milligrams × 0.001), or use the milligrams-to-grams page.

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Machine access

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