 Mass Calculators:
 OnLine Exact Mass Calculator  Type in the formula
and it will calculate the exact mass.
 Alternatively, you may wish to download software to use at your desktop, try the Molecular Weight Calculator for windows.
 If you prefer to calculate masses manually then use the Table of Atomic Masses current as of 1995. When calculating exact mass
keep in mind that some instruments account for the mass of the electron
(observe charged species by mass spectrometry) and some do not.
This table of ION masses may be helpful when
considering exact mass measurements for electrospray ions.
 Protein / Peptide Utilities:
 OnLine  Protein Prospector at UCSF  besides database searching there are many helpful utilities here
including theoretical digests, theoretical peptide fragmentation, possible amino acid compositions for a given mass, etc.
