Microgram is 0.000001 gram units.
Micrograms to Milligrams Converter — ug to mg
Convert Microgram (ug) to Milligram (mg) using the exact conversion factor (1 microgram = 0.001 milligram). See the formula, worked examples, and conversion table.
Micrograms to Milligrams converter
Converter
Scientific Units Converter
Convert SI derived units, scientific notation-friendly units, atomic units, and lab measurements.
Context values
Some unit families need one extra value for a physically accurate result.
Milligram is 0.001 gram units.
Result = input x 1e-9 / 1e-6.
Mass units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Micrograms to Milligrams
Microgram and Milligram are both scientific-measurement units, spanning everything from atomic and laboratory scales to astronomical distances — the kind of conversion that comes up constantly in physics, chemistry, and astronomy when a result needs to move between conventions used in different subfields. Specifically: Microgram is 0.000001 gram units, and milligram is 0.001 gram units.
Formula
milligrams = micrograms × 0.001
This factor comes from each unit's defined relationship to the category's base unit: 1 microgram equals 1e-9 base units, and 1 milligram equals 0.000001 base units, so dividing one by the other gives the direct microgram-to-milligram factor of 0.001.
Simple example
1 ug × 0.001 = 0.001 mg
1 microgram = 0.001 milligrams.
Real-world example
10 ug × 0.001 = 0.01 mg
10 micrograms = 0.01 milligrams.
Conversion table
| Microgram (ug) | Milligram (mg) |
|---|---|
| 0.001 ug | 0.000001 mg |
| 0.01 ug | 0.00001 mg |
| 1 ug | 0.001 mg |
| 10 ug | 0.01 mg |
| 100 ug | 0.1 mg |
| 1,000 ug | 1 mg |
Reverse conversion: Milligram to Microgram
0.001 mg × 1000 = 1 ug
0.001 milligrams = 1 microgram.
micrograms = milligrams × 1000
For a page dedicated to this direction, see Milligram to Microgram.
Understanding the Microgram (ug)
Microgram is 0.000001 gram units.
Understanding the Milligram (mg)
Milligram is 0.001 gram units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many milligrams are in 1 microgram?
1 microgram equals 0.001 milligrams, using the exact defined conversion factor rather than an estimate.
How do I convert microgram to milligram?
Multiply the microgram value by 0.001. The converter above does this instantly to whatever precision you set.
How do I convert milligram back to microgram?
Use the reverse factor: 1 milligram equals 1,000 micrograms. You can also use the swap control in the converter above to flip the direction instantly.
What is a microgram?
Microgram (ug) is a unit of scientific units.
What is a milligram?
Milligram (mg) is a unit of scientific units.
Is the microgram to milligram conversion exact?
Yes. Both microgram and milligram are defined by fixed standards rather than physical artifacts, so the factor of 0.001 used above is exact to as many digits as you choose to display.
Why does this category span everything from atomic to astronomical scales?
Scientific work spans an enormous range of physical scales, from atomic distances (measured in angstroms or atomic mass units) to interstellar distances (measured in astronomical units or parsecs), so this category groups SI-derived and scale-specific units that researchers commonly need to convert between within their field.