What is an atomic mass unit (AMU)?

An atomic mass unit (AMU) is a standard unit of mass that quantifies mass on an atomic or molecular scale. 1 AMU is defined as one twelfth of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state, approximately 1.66053906660 × 10^-27 kilograms.

How do you convert AMU to kilograms?

To convert AMU to kilograms, multiply the number of AMU by 1.66053906660 × 10^-27 kg. For example, 12 AMU (carbon-12 atom) equals 12 × 1.66053906660 × 10^-27 = 1.99264687992 × 10^-26 kg.

Why is carbon-12 used as the standard for AMU?

Carbon-12 was chosen as the standard because it's a common, stable isotope that forms strong covalent bonds, making it easy to work with experimentally. Its atomic mass is close to a whole number, simplifying calculations, and it's abundant in nature.

Atomic Mass Unit (AMU) Converter

Convert between atomic mass units and kilograms instantly

Atomic Mass Units (AMU)

Kilograms (kg)

Atomic Mass Unit Formula

1 AMU = 1.66053906660 × 10^-27 kilograms

This precise conversion factor is based on the unified atomic mass unit (u) standard.

Why AMU Conversion Matters:

"Atomic mass unit" and related terms are commonly searched because:

Chemistry students need to understand atomic scale measurements
Researchers work with subatomic particle masses
AMU is fundamental to stoichiometry calculations
Understanding AMU helps grasp nuclear physics concepts

Key Atomic Masses:

Hydrogen-1

~1.0078 AMU (lightest element)

Carbon-12

Exactly 12 AMU (standard reference)

Uranium-238

~238.0508 AMU (heavy natural isotope)

Understanding Atomic Mass Units (AMU) in Chemistry

The atomic mass unit (AMU), also known as the unified atomic mass unit (u) or dalton (Da), is a fundamental concept in chemistry and physics. This tiny unit of mass allows scientists to work with the incredibly small masses of atoms and subatomic particles. Our AMU calculator makes it easy to convert between atomic mass units and kilograms.

The Science Behind Atomic Mass Units

An atomic mass unit is defined as 1/12 of the mass of a carbon-12 atom at rest. This equals approximately 1.66053906660 × 10^-27 kilograms. The carbon-12 standard was adopted internationally in 1961, replacing the oxygen standard previously used.

Key Insight: While 1 AMU is approximately the mass of a single proton or neutron, these particles actually have slightly different masses (proton: ~1.0073 AMU, neutron: ~1.0087 AMU). This difference is crucial in nuclear physics.

Practical Applications of AMU

Our AMU converter helps with various scientific applications:

Calculating molecular weights in chemical reactions
Determining isotopic abundances in mass spectrometry
Understanding nuclear binding energies
Quantum chemistry calculations
Stoichiometry in chemical equations

Related Resources

For more information about atomic mass units and chemistry concepts, explore these authoritative resources:

How Our AMU Converter Works

Disclaimer

This AMU converter uses the standard unified atomic mass unit (u) value as defined by IUPAC. For most chemistry applications, this precision is sufficient. However, for nuclear physics or high-precision work, additional factors like electron binding energy may need consideration. Always verify critical calculations with authoritative sources.