Convert Microgram to Milligram
Convert micrograms to milligrams instantly. 1 microgram = 0.001 milligram — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Milligram to Microgram converter for the reverse conversion.
Units explained
Microgram
A microgram (ug) equals 10^-9 kilogram, or one-millionth of a gram.
From the SI prefix 'micro-' (from Greek 'mikros', small).
Trace nutrients, potent drug doses, and environmental contaminant levels.
The micro- prefix was incorporated into the SI in 1960.
Milligram
A milligram (mg) equals one-millionth of a kilogram, or 0.001 gram.
From the SI prefix 'milli-' (from Latin 'mille', thousand).
Standard for medicine dosing, nutrition labels, and fine jewelry.
Part of the original metric system of 1795.
Microgram to Milligram conversion formula
The relationship between micrograms and milligrams:
To convert micrograms to milligrams, multiply the value in micrograms by 0.001. To reverse, multiply milligrams by 1000.
How to use this converter
Type a value into the calculator. The result in milligrams updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Milligram to Microgram converter for the reverse direction.
Step-by-step: convert micrograms to milligrams
- Write down the value in micrograms (µg).
- Multiply that value by the factor 0.001.
- The product is the equivalent value in milligrams (mg).
- To reverse, multiply the milligram value by 1000.
Worked examples
Example 1 — Convert 1 µg to mg:
1 × 0.001 = 0.001 mg
Example 2 — Convert 100 µg to mg:
100 × 0.001 = 0.1 mg
Real-world example — Spanning sub-micron to micron scale
Crossing from micrograms to milligrams is the everyday workflow of microscopy and semiconductor engineering — a measurement of 1000 micrograms translates to a much more compact value in milligrams that fits the scale of biological cells and process nodes.
1000 µg × 0.001 = 1 mg
Real-world example — Sub-visible-light wavelength
500 micrograms (the green-yellow visible band) equals 0.5 milligrams — the canonical conversion in optics between wavelength specifications and micron-scale lens-coating thicknesses.
500 µg × 0.001 = 0.5 mg
Microgram to Milligram conversion table
Standard reference values for converting micrograms to milligrams:
| Microgram [µg] | Milligram [mg] |
|---|---|
| 0.01 | 1e-5 |
| 0.1 | 0.0001 |
| 1 | 0.001 |
| 2 | 0.002 |
| 3 | 0.003 |
| 4 | 0.004 |
| 5 | 0.005 |
| 10 | 0.01 |
| 20 | 0.02 |
| 30 | 0.03 |
| 40 | 0.04 |
| 50 | 0.05 |
| 100 | 0.1 |
| 500 | 0.5 |
| 1000 | 1 |
Frequently asked questions
How many milligrams is 1 microgram?
How do I convert micrograms to milligrams?
How do I convert milligrams back to micrograms?
How many milligrams is 100 micrograms?
Popular weight unit conversions
Convert Microgram to other weight units
Show all Microgram conversions
Metric / SI (17 units)
Avoirdupois (15 units)
Troy & Apothecary (10 units)
Indian / South Asian (6 units)
Scientific / Atomic (9 units)
Astronomical (4 units)
Biblical / Ancient (14 units)
Sources & references
Conversion factor (1 µg = 0.001 mg) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.