Grams to Milligrams Calculator
Enter a value in grams (g) to convert it to milligrams (mg).
Milligrams to Grams Calculator
Enter a value in milligrams (mg) to convert it to grams (g).
Weight Unit Converter
Convert between grams, milligrams, kilograms, micrograms, ounces, and pounds.
How to Convert Grams to Milligrams
The relationship between grams and milligrams is straightforward. The prefix milli means one thousandth, so one gram equals exactly 1,000 milligrams. To convert grams to milligrams, multiply the number of grams by 1,000.
Example: 2.5 g x 1,000 = 2,500 mg
How to Convert Milligrams to Grams
To convert milligrams back to grams, divide the number of milligrams by 1,000.
Example: 750 mg / 1,000 = 0.75 g
Grams and Milligrams in Everyday Life
Milligrams are commonly used in medicine and nutrition. Vitamin and mineral supplements, prescription drugs, and food nutrition labels all use milligrams to express small quantities. For example, a standard aspirin tablet contains 500 mg, which is 0.5 g. Grams are used for measuring food portions, cooking ingredients, and the weight of small objects.
The Metric Weight System
1 gram (g) = 1,000 milligrams (mg)
1 milligram (mg) = 1,000 micrograms (mcg)
1 gram (g) = 1,000,000 micrograms (mcg)
Grams to Ounces and Pounds
1 gram = 0.002205 pounds (lb)
1 ounce = 28.3495 grams
1 pound = 453.592 grams
Common Medication Weights
Understanding milligrams is especially useful when reading medication labels. Doses are almost always listed in milligrams. Here are some common reference points:
Vitamin C supplement: 1,000 mg = 1 g
Iron supplement: 65 mg = 0.065 g
Vitamin D: 25 mcg = 0.000025 g