Convert Milligram to Gram (mg → g)

Converting milligrams to grams is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in milligrams

   Start with the number of milligrams (mg) you want to convert.
2. 2
   Multiply by 0.001

   The conversion factor from mg to g is 0.001. Multiply your value by this number.
3. 3
   Read the result in grams

   The result is your value in grams (g).

Multiply the value in milligrams by 0.001. For the reverse direction, multiply by 1,000.

• ✓1 mg = 1/1000 g = 1,000,000 µg. Always check which prefix the label uses.
• ✓Read medication labels carefully — confusing mg and µg can be a 1000× dosing error.
• ✓Nutrition labels list minerals in mg and vitamins (A, D, K) in µg.

• ✗Reading 500 mg as 500 g on a medicine bottle — a potentially fatal 1000× error.
• ✗Confusing mg (milligram) with mg/kg (dose per kilogram of body weight).
• ✗Mixing up mg and µg — µg is 1000× smaller.

What is the Milligram?

The milligram equals one thousandth of a gram (0.001 g) or 10⁻⁶ kilograms, and is the standard unit for pharmaceutical dosing, vitamin labeling, food additives, and chemistry laboratory work. A typical aspirin tablet contains 325–500 mg of active ingredient, and recommended daily vitamin C intake is around 75–90 mg. The milligram is essential in toxicology (LD50 values are often given in mg per kg of body weight), water-quality testing (dissolved minerals in mg/L), and trace-element analysis. It relates to the gram (1,000 mg = 1 g), the microgram (1,000 µg = 1 mg), and the grain (1 grain ≈ 64.8 mg). Pharmaceutical prescriptions worldwide rely on milligrams, and accurate sub-milligram balances are standard in research and pharmacy environments.

• Prescription and over-the-counter drug dosing
• Vitamin and mineral supplement labelling
• Trace element analysis in laboratories

What is the Gram?

The gram equals one thousandth of a kilogram (0.001 kg) and is the everyday metric unit for cooking ingredients, postage, jewelry, pharmaceuticals, and small product weights. Originally defined in 1795 as 'the absolute weight of a volume of pure water equal to a cube of one hundredth of a meter at the temperature of melting ice,' the gram is now formally defined via the kilogram. It relates simply to the milligram (1,000 mg = 1 g) and the kilogram (1,000 g = 1 kg). European nutrition labels universally use grams for ingredient quantities, and recipes worldwide outside North America measure ingredients by mass in grams rather than by volume. Gold and silver are traded in grams for small quantities, while gemstones use carats (0.2 g = 1 carat). A standard paper clip weighs about 1 g.

• European cooking and baking recipes
• Over-the-counter medication dosages
• Gold, silver and gemstone retail (per gram pricing)