Convert Atomic Mass Unit to Milligram
Convert atomic mass unit to milligrams instantly. 1 atomic mass unit = 1.66054e-21 milligram — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Milligram to Atomic Mass Unit converter for the reverse conversion.
Units explained
Atomic Mass Unit
One unified atomic mass unit (u) is defined as 1/12 the mass of a carbon-12 atom, about 1.6605E-27 kg.
Introduced to give atomic and molecular masses convenient numerical values.
Atomic, molecular, and nuclear physics and chemistry.
The unified (carbon-12) scale was adopted by IUPAC and IUPAP in 1960-1961.
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.
Atomic Mass Unit to Milligram conversion formula
The relationship between atomic mass unit and milligrams:
To convert atomic mass unit to milligrams, multiply the value in atomic mass unit by 1.66054e-21. To reverse, multiply milligrams by 6.022137e+20.
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 Atomic Mass Unit converter for the reverse direction.
Step-by-step: convert atomic mass unit to milligrams
- Write down the value in atomic mass unit (u).
- Multiply that value by the factor 1.66054e-21.
- The product is the equivalent value in milligrams (mg).
- To reverse, multiply the milligram value by 6.022137e+20.
Worked examples
Example 1 — Convert 1 u to mg:
1 × 1.66054e-21 = 1.66054e-21 mg
Example 2 — Convert 100 u to mg:
100 × 1.66054e-21 = 1.66054e-19 mg
Real-world example — Spanning sub-micron to micron scale
Crossing from atomic mass unit to milligrams is the everyday workflow of microscopy and semiconductor engineering — a measurement of 1000 atomic mass unit translates to a much more compact value in milligrams that fits the scale of biological cells and process nodes.
1000 u × 1.66054e-21 = 1.66054e-18 mg
Real-world example — Sub-visible-light wavelength
500 atomic mass unit (the green-yellow visible band) equals 0.5 milligrams — the canonical conversion in optics between wavelength specifications and micron-scale lens-coating thicknesses.
500 u × 1.66054e-21 = 8.302701e-19 mg
Atomic Mass Unit to Milligram conversion table
Standard reference values for converting atomic mass unit to milligrams:
| Atomic Mass Unit [u] | Milligram [mg] |
|---|---|
| 0.01 | 1.66054e-23 |
| 0.1 | 1.66054e-22 |
| 1 | 1.66054e-21 |
| 2 | 3.32108e-21 |
| 3 | 4.981621e-21 |
| 4 | 6.642161e-21 |
| 5 | 8.302701e-21 |
| 10 | 1.66054e-20 |
| 20 | 3.32108e-20 |
| 30 | 4.981621e-20 |
| 40 | 6.642161e-20 |
| 50 | 8.302701e-20 |
| 100 | 1.66054e-19 |
| 500 | 8.302701e-19 |
| 1000 | 1.66054e-18 |
Frequently asked questions
How many milligrams is 1 atomic mass unit?
How do I convert atomic mass unit to milligrams?
How do I convert milligrams back to atomic mass unit?
How many milligrams is 100 atomic mass unit?
Popular weight unit conversions
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Metric / SI (18 units)
Avoirdupois (15 units)
Troy & Apothecary (10 units)
Indian / South Asian (6 units)
Scientific / Atomic (8 units)
Astronomical (4 units)
Biblical / Ancient (14 units)
Sources & references
Conversion factor (1 u = 1.66054e-21 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.