gram
gmass · International · Modern
1 g = 0.001 kg.
Converter
mass · International · Modern
dalton / unified atomic mass unit
Da; uapprox.
- Record
- M489
- Definition quality
- Standardized
- Conversion mode
- multiplicative
- Calculator
- Approximately calculable
Definition
Dalton/u is 1/12 of the mass of a free carbon-12 atom in its ground state. CODATA 2022: 1.66053906892(52)×10^-27 kg.
Reference value
One dalton / unified atomic mass unit is understood to be about 1.660539 × 10^-27 kilograms.
History & use
Used for atomic/molecular masses.
Modern use
Current-use record in the project inventory; exact scope should follow the definition and regional/system context shown here.
Did you know?
Its kg conversion is not exact in the revised SI.
Sources & evidence
Source tier Tier A · confidence High
Related measurements
kilogram
kgmass · International · Modern
SI base unit of mass. The Planck constant is fixed exactly at 6.62607015×10^-34 J·s, which defines the kilogram through the metre and second.
mass · International · Modern
1 tonne = 1000 kg.
mass · UK / US · Modern / historical
1 avoirdupois ounce = exactly 1/16 international pound = 0.028349523125 kg.
mass · UK / US · Modern / historical
1 international avoirdupois pound = exactly 0.45359237 kg.
stone
stmass · UK / US · Modern / historical
1 stone = 14 lb = exactly 6.35029318 kg using the international pound.
mass · Ancient Greece / Rome · Antiquity
Greek talent was not one universal standard.
variantmass · Ancient Greece / Rome · Antiquity
Modern scholarship cautions that proposed SI values span roughly 322.56–330 g.
approx.