SI jedinica molekulske mase je kilogram. Međutim. za proučavanje molekulske mase češće se upotrebljava jedinica atomske mase (simbol u ili Da). Primjerice, molekulska masa vode je približno:
^Kornberg A. (1989): For the love of enzymes – The Odyssay of a biochemist. Harvard University Press, Cambridge (Mass.), London,ISBN0-674-30775-5, ISBN0-674-30776-3.
^Hunter G. K. (2000): Vital Forces. The discovery of the molecular basis of life. Academic Press, London 2000, ISBN0-12-361811-8.
^Nelson D. L., Cox M. M. (2013): Lehninger Principles of Biochemistry. W. H. Freeman and Co., ISBN978-1-4641-0962-1.