Dalton (unit)

unit of mass defined as ¹⁄₁₂ of the mass of a carbon-12 atom
(Redirected from Atomic mass unit)

The dalton or unified atomic mass unit (abbreviated: amu, u, or Da) is a unit of measurement that is used to measure the mass of atoms. The atomic mass unit is equal to one twelfth of the mass of the carbon-12.

The unified atomic mass unit and the dalton are different names for the same thing. The word 'dalton' is being used more over time.[1][2][3] The unit is named after John Dalton, an 18th-century naturalist and teacher.


  1. Mills, Ian; Cvitaš, Tomislav; Homann, Klaus; Kallay, Nikola; Kuchitsu, Kozo (1993). Quantities, Units and Symbols in Physical Chemistry International Union of Pure and Applied Chemistry; Physical Chemistry Division (PDF) (2nd ed.). International Union of Pure and Applied Chemistry and published for them by Blackwell Science Ltd. ISBN 0-632-03583-8.
  2. "Consultative Committee for Units (CCU); Report of the 15th meeting (17 –18 April 2003) to the International Committee for Weights and Measures" (PDF). Archived from the original (PDF) on 7 June 2011. Retrieved 14 Aug 2010.
  3. "IU14. IUPAC Interdivisional Committee on Nomenclature and Symbols (ICTNS)". Archived from the original on 2011-06-14. Retrieved 2010-08-14.