Mass and Weight · Unit Converter

Convert Atomic Mass Unit to Carbon-12 Atom Mass

Convert atomic mass unit to carbon-12 atom mass instantly. 1 atomic mass unit = 0.0833333902 carbon-12 atom mass — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Carbon-12 Atom Mass to Atomic Mass Unit converter for the reverse conversion.

Written by Sunith Babu L, Ph.D., Lead Engineer Reviewed by Dr. Ashok Kumar K, Ph.D.
Mass and Weight category 2 min read Published Last reviewed Updated

Units explained

Scientific / Atomic

Atomic Mass Unit

What is a 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.

Origin of the atomic mass unit

Introduced to give atomic and molecular masses convenient numerical values.

Where it is used

Atomic, molecular, and nuclear physics and chemistry.

When and where it was developed

The unified (carbon-12) scale was adopted by IUPAC and IUPAP in 1960-1961.

Scientific / Atomic

Carbon-12 Atom Mass

What is a carbon-12 atom mass?

The mass of a single carbon-12 atom is exactly 12 u by definition, about 1.9926E-26 kg.

Origin of the carbon-12 atom mass

The reference nuclide that defines the unified atomic mass scale.

Where it is used

The defining standard for the atomic mass unit.

When and where it was developed

Chosen as the mass standard by IUPAC and IUPAP in 1960-1961.

Atomic Mass Unit to Carbon-12 Atom Mass conversion formula

The relationship between atomic mass unit and carbon-12 atom mass:

1 u = 0.0833333902 C-12
1 C-12 = 11.9999918099 u

To convert atomic mass unit to carbon-12 atom mass, multiply the value in atomic mass unit by 0.0833333902. To reverse, multiply carbon-12 atom mass by 11.9999918099.

How to use this converter

Type a value into the calculator. The result in carbon-12 atom mass updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Carbon-12 Atom Mass to Atomic Mass Unit converter for the reverse direction.

Step-by-step: convert atomic mass unit to carbon-12 atom mass

  1. Write down the value in atomic mass unit (u).
  2. Multiply that value by the factor 0.0833333902.
  3. The product is the equivalent value in carbon-12 atom mass (C-12).
  4. To reverse, multiply the carbon-12 atom mass value by 11.9999918099.

Worked examples

Example 1 — Convert 1 u to C-12:
1 × 0.0833333902 = 0.0833333902 C-12

Example 2 — Convert 100 u to C-12:
100 × 0.0833333902 = 8.3333390209 C-12

Real-world example — Wavelengths across the spectrum

Optical and atomic-scale phenomena are routinely cross-converted between sub-micron units. A photon of wavelength 800 atomic mass unit can be re-expressed in carbon-12 atom mass for direct comparison with another instrument's calibration data sheet.

800 u × 0.0833333902 = 66.6667121673 C-12

Real-world example — Molecular dimensions

The diameter of small molecular structures (around 2 atomic mass unit) is often converted into related sub-micron units when comparing measurements across different microscopy techniques or imaging modalities.

2 u × 0.0833333902 = 0.1666667804 C-12

Atomic Mass Unit to Carbon-12 Atom Mass conversion table

Standard reference values for converting atomic mass unit to carbon-12 atom mass:

Atomic Mass Unit [u]Carbon-12 Atom Mass [C-12]
0.010.0008333339
0.10.008333339
10.0833333902
20.1666667804
30.2500001706
40.3333335608
50.416666951
100.8333339021
201.6666678042
302.5000017063
403.3333356084
504.1666695105
1008.3333390209
50041.6666951046
100083.3333902091

Frequently asked questions

How many carbon-12 atom mass is 1 atomic mass unit?
1 atomic mass unit equals 0.0833333902 carbon-12 atom mass.
How do I convert atomic mass unit to carbon-12 atom mass?
Multiply the value in atomic mass unit by 0.0833333902 to get carbon-12 atom mass.
How do I convert carbon-12 atom mass back to atomic mass unit?
Multiply the value in carbon-12 atom mass by 11.9999918099, or use the Carbon-12 Atom Mass to Atomic Mass Unit converter.
How many carbon-12 atom mass is 100 atomic mass unit?
100 atomic mass unit equals 8.3333390209 carbon-12 atom mass, because 100 × 0.0833333902 = 8.3333390209.

Convert Atomic Mass Unit to other weight units

Show all Atomic Mass Unit conversions
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)
Force / Engineering (5 units)

Sources & references

Conversion factor (1 u = 0.0833333902 C-12) verified against the following authoritative sources:

Results are provided for general reference. Verify critical measurements against an authoritative standard.