Milligrams to Micrograms
Convert milligrams to micrograms instantly — one milligram is 1000 micrograms.
| Milligrams | Micrograms |
|---|---|
| 1 mg | 1000 µg |
| 2 mg | 2000 µg |
| 3 mg | 3000 µg |
| 5 mg | 5000 µg |
| 10 mg | 10000 µg |
| 25 mg | 25000 µg |
| 50 mg | 50000 µg |
| 100 mg | 100000 µg |
How to use
- Enter a value in the Milligrams field.
- The Micrograms figure appears immediately — no button to press.
- Typing in the Micrograms field converts back to Milligrams the same way.
- Use the reference table for the values that come up most often.
Milligrams to Micrograms formula
To convert milligrams to micrograms, multiply by 1000.
µg = mg × 1000
Put another way, one milligram is exactly 1,000 micrograms.
Why this factor: the milligram and the microgram are both defined against the kilogram, so dividing one definition by the other gives 1000 directly. Both definitions are set out in full below.
To go the other way, divide by 1000 — or use the Micrograms to Milligrams converter, which is the same calculation reversed.
Worked example
Given 25 mg, multiplying by 1000 yields 25000 µg.
25 mg × 1000 = 25000 µg
The converter above does this for any value you type, in either direction.
What is a milligram?
A milligram is one thousandth of a gram — the standard unit for drug doses and micronutrients.
Definition: Exactly 1×10⁻⁶ kilogram by SI prefix definition.
Where it is used: Medication dosages, vitamin and mineral content, and analytical chemistry.
What is a microgram?
A microgram is one millionth of a gram, used where quantities are vanishingly small but still matter.
Definition: Exactly 1×10⁻⁹ kilogram by SI prefix definition. Symbol µg.
Where it is used: Trace nutrients such as vitamin B12 and folate, hormone doses, and air-quality measurements.
Worth knowing: Sometimes abbreviated 'mcg' on labels specifically to avoid µg being misread as mg — a thousandfold dosing error.
Milligrams vs Micrograms
The milligram and the microgram belong to the same family of units, so converting between them is usually a matter of shifting a decimal point or applying a small whole-number factor.
Frequently asked questions
How many micrograms are in a milligram?
One milligram equals 1000 micrograms.
What is the formula to convert milligrams to micrograms?
Multiply the number of milligrams by 1000. To reverse it, divide by 1000 instead.
How do I convert micrograms back to milligrams?
Divide by 1000, which is the same as multiplying by 0.001.
How many micrograms are in 10 milligrams?
10 mg works out to 10000 µg.
Is there anything to watch out for with micrograms?
Sometimes abbreviated 'mcg' on labels specifically to avoid µg being misread as mg — a thousandfold dosing error.
How is the milligram defined?
Exactly 1×10⁻⁶ kilogram by SI prefix definition.