Molecular Mass Calculator

How to calculate the mass of a
particular isotopic composition

Enter the molecular formula of the molecule.
Examples: C6H12O6, PO4H2(CH2)12CH3

Standard Masses

Standard Formula Weight:   64.130000

Mono-isotopic molecular masses:
12C/14N:    511.0516529944
13C/14N:    532.1221045882
12C/15N:    514.0427576740
13C/15N:    535.1132092678

Calculate molecular mass by:

Molecular Mass for C21H27N3OPS2Br = 512.468948 Da

Charge = 0

12C    12.000000
13C    13.003355
14C    14.003242

Average mass of this isotopic composition of C: 12.010736 Da


1H    1.007825
2H (D)   2.014102
3H (T)   3.016049

Average mass of this isotopic composition of H: 1.007941 Da


79Br    78.918338
81Br    80.916291

Average mass of this isotopic composition of Br: 79.903528 Da


14N    14.003074
15N    15.000109

Average mass of this isotopic composition of N: 14.006743 Da


16O    15.994915
17O    16.999132
18O    17.999160

Average mass of this isotopic composition of O: 15.999405 Da


31P    30.973762

Average mass of this isotopic composition of P: 30.973762 Da


32S    31.972071
33S    32.971458
34S    33.967867
36S    35.967081

Average mass of this isotopic composition of S: 32.066085 Da




Masses and Isotopic Compositions came from the NIST Physical Reference Data
*This mass was calculated from the distribution displayed in the text inputs.