Convert Atomic Mass Unit to Kilogram
Convert atomic mass unit to kilograms instantly. 1 atomic mass unit = 1.66054e-27 kilogram — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Kilogram 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.
Kilogram
The kilogram (kg) is the SI base unit of mass, defined by fixing the Planck constant h at 6.62607015E-34 J s.
From Greek 'khilioi' (thousand) plus 'gramma' (small weight).
The worldwide base unit of mass in science, commerce, and everyday life.
Adopted in 1795; redefined through the Planck constant on 20 May 2019.
Atomic Mass Unit to Kilogram conversion formula
The relationship between atomic mass unit and kilograms:
To convert atomic mass unit to kilograms, multiply the value in atomic mass unit by 1.66054e-27. To reverse, multiply kilograms by 6.022137e+26.
How to use this converter
Type a value into the calculator. The result in kilograms updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Kilogram to Atomic Mass Unit converter for the reverse direction.
Step-by-step: convert atomic mass unit to kilograms
- Write down the value in atomic mass unit (u).
- Multiply that value by the factor 1.66054e-27.
- The product is the equivalent value in kilograms (kg).
- To reverse, multiply the kilogram value by 6.022137e+26.
Worked examples
Example 1 — Convert 1 u to kg:
1 × 1.66054e-27 = 1.66054e-27 kg
Example 2 — Convert 100 u to kg:
100 × 1.66054e-27 = 1.66054e-25 kg
Real-world example — From sub-micron to human scale
One billion atomic mass unit equals one kilogram — the conversion that drives home the gulf between atomic-scale features and everyday objects in physics curricula.
1e+9 u × 1.66054e-27 = 1.66054e-18 kg
Real-world example — Bridging nine orders of magnitude
500 million atomic mass unit equals a value comfortably in the human-scale kilograms range. Physics problems that span this gap are common when comparing the wavelength of light to the path length of an experiment.
5e+8 u × 1.66054e-27 = 8.302701e-19 kg
Atomic Mass Unit to Kilogram conversion table
Standard reference values for converting atomic mass unit to kilograms:
| Atomic Mass Unit [u] | Kilogram [kg] |
|---|---|
| 0.01 | 1.66054e-29 |
| 0.1 | 1.66054e-28 |
| 1 | 1.66054e-27 |
| 2 | 3.32108e-27 |
| 3 | 4.981621e-27 |
| 4 | 6.642161e-27 |
| 5 | 8.302701e-27 |
| 10 | 1.66054e-26 |
| 20 | 3.32108e-26 |
| 30 | 4.981621e-26 |
| 40 | 6.642161e-26 |
| 50 | 8.302701e-26 |
| 100 | 1.66054e-25 |
| 500 | 8.302701e-25 |
| 1000 | 1.66054e-24 |
Frequently asked questions
How many kilograms is 1 atomic mass unit?
How do I convert atomic mass unit to kilograms?
How do I convert kilograms back to atomic mass unit?
How many kilograms 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-27 kg) 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 Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.