Convert Microgram to Milligram (µg → mg)

Converting micrograms to milligrams 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 micrograms

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

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

   The result is your value in milligrams (mg).

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

• ✓1 µg = 0.001 mg = 1/1,000,000 g.
• ✓Some older labels write "mcg" instead of µg — both mean the same thing.
• ✓For very small doses prefer µg to avoid decimal confusion (0.025 mg vs. 25 µg).

• ✗Treating mcg and mg as equivalent on older prescription pads.
• ✗Typing "mg" when the intended unit is "µg" — a 1000× overdose.
• ✗Reading µg as g without the prefix — a 1-million-fold error.

What is the Microgram?

The microgram equals one millionth of a gram (10⁻⁶ g) and is the standard unit for very small mass measurements in pharmacology, environmental science, and trace-element nutrition. The Greek letter µ (mu) represents the SI prefix 'micro' (one millionth). Vitamin B12 daily intake is around 2.4 µg, and the lethal dose of botulinum toxin is in the nanogram-to-microgram range, making it one of the most potent biological substances known. The microgram is critical in air-quality monitoring (PM concentrations in µg/m³), trace-mineral supplements (selenium, iodine), and pharmaceutical compounding. It relates to the milligram (1,000 µg = 1 mg) and the nanogram (1,000 ng = 1 µg). Environmental regulators set legal limits on heavy metals (lead, arsenic) in drinking water in micrograms per liter.

• Vitamin D, A and K dosing
• Trace metal content in food and water
• Hormone replacement therapy dosing

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