# Atomic Mass Constant

Use Atomic Mass in Calcul.io. See what this built-in constant represents, enter it in an editable calculation, and review related values and units.

## atomicMass

Atomic mass constant

Try it yourself:

```calculio
atomicMass
```

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## Atomic Mass Constant

The atomic mass constant, **atomicMass**, is one twelfth of the mass of a carbon-12 atom. It converts atomic-scale masses into SI kilograms.

## Use in calculations

Combine it with [avogadro](https://calcul.io/constants/avogadro/index.md) and [molarMass](https://calcul.io/constants/molarMass/index.md) when moving between particle and molar quantities. Keep units explicit; atomic mass units and kilograms are not interchangeable without conversion.

[All constants](https://calcul.io/constants/index.md)