Axis

Mass & weight

daltonDa

One twelfth of the mass of a carbon-12 atom; the atomic mass unit.

Dimension
mass
Canonical signature
M
System
si accepted
Exactness
Exact by definition

Definition record

How this unit is defined

Canonical base
1 Da = 1.6605390666e-27 kg
Conversion type
linear
Historical notes
CODATA 2018 value; 1 Da = 1.660 539 066 60 × 10⁻²⁷ kg.
Aliases
atomic mass unit, amu, u, unified atomic mass unit, daltons

Same dimension

Related units

kilogramsikggramsigpoundimperial uslbmass ounceimperial usoztonnesi acceptedtmilligramsimgmicrogramsiµgnanogramsing

Common conversions

Every conversion routes through the canonical base of the dimension.

1 Da = 1.6605390666e-27 kg

Exact by definition relationship

10 Da = 1.6605390666e-26 kg

Exact by definition relationship