Milligrams to Grams (mg to g)

How to convert milligrams to grams

Divide the milligrams by 1,000:

g = mg ÷ 1,000

500 mg ÷ 1,000 = 0.5 g. Dividing by 1,000 moves the decimal point three places to the left:

The prefixes are exact: milli- means one thousandth. The result also shows micrograms and ounces. To go the other way, multiply by 1,000.

Milligrams to grams chart

Milligrams on nutrition labels

U.S. Nutrition Facts panels give sodium, cholesterol, potassium and most vitamins and minerals in milligrams, and fat, carbohydrate and protein in grams. Converting puts them on one scale: 2,300 mg of sodium is 2.3 g, and a serving with 460 mg has a fifth of that. Dietary supplements list milligrams per tablet; the label’s serving size tells you how many tablets that is. This page converts units — it does not give dosing advice; follow the label or a pharmacist for medicine.

Milligrams in the kitchen and the lab

Kitchen scales rarely read below 1 gram, so amounts in milligrams — a pinch of saffron, a dose of citric acid for canning, yeast for a single loaf scaled down — need a jeweler’s scale that reads to 0.01 g (10 mg) or 0.001 g (1 mg). In a chemistry lab, balances read in grams to four decimal places, and the last place is a tenth of a milligram, so 0.0250 g on the display means 25.0 mg. A common slip is writing 0.25 g for 25 mg; counting the places after the decimal point — three for milligrams — catches it.

Milligrams, micrograms and grams

Below the milligram is the microgram (mcg or µg), a thousandth of a milligram, used for vitamin D, B12 and folate; see mcg to mg. Above the gram is the kilogram, 1,000 g; see grams to kg. Each step is a factor of 1,000, so the same rule of moving the decimal point by three places works all the way. For ounces, the U.S. kitchen unit, use grams to ounces: an ounce is 28,349.5 mg.