g to mg Converter

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Convert grams to milligrams using the SI relation 1 g = 1,000 mg. Most common when pharmacy or supplement labels report a gram-level total but the dosing instructions or split tablets are stated in milligrams (a 2 g daily dose split across four 500 mg pills, for example). Browser-local — your inputs stay on your device.

Gram (g)
Milligram (mg)

Gram (g) → Milligram (mg)

Quick reference table

Gram (g)Milligram (mg)
1 g1000 mg
2 g2000 mg
5 g5000 mg
10 g10000 mg
25 g25000 mg
50 g50000 mg
100 g100000 mg

Glossary

Gram (g)

A gram is one thousandth of a kilogram (1 g = 1000 mg = 0.001 kg). It is the everyday metric unit for cooking ingredients, postal weights, jewellery and small-package retail. One US nickel weighs 5 g; a standard letter envelope tops out at about 30 g for the lowest postage tier.

Milligram (mg)

A milligram is one thousandth of a gram and one millionth of a kilogram (1 mg = 0.001 g). It is the standard unit for medication dosages, vitamin labelling, fine-chemistry measurements and food nutrient content. A typical aspirin tablet is around 325 mg; a daily vitamin C dose is often 60–1000 mg.

Metric system (SI)

The metric system is a decimal system of measurement built around the kilogram for mass, the meter for length and the second for time, with multiples and submultiples expressed as powers of ten (milligram, gram, tonne). Adopted in France in 1799 and codified internationally as the International System of Units (SI) in 1960, it is now the official system in nearly every country and the standard in science.

Imperial / US Customary system

The imperial system is the historical English system of weights and measures whose mass units are the ounce, pound, stone and ton (16 oz = 1 lb, 14 lb = 1 stone, 2,000 lb = 1 US short ton). Codified by the British Weights and Measures Act of 1824 and aligned with US Customary by the 1959 international yard-and-pound agreement (1 lb = 0.45359237 kg exactly), it is still used in the United States and the United Kingdom for everyday weights.

Related tools

Milligrams to Grams
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Convert grams to ounces — 1 g = 0.03527 oz (1 oz = 28.3495 g)
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