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Isotope Distribution Calculator and Mass Spec Plotter

Description of this Program Page. Description of this Program Page.
    This progrm has been produced by Scientific Instrument Services for use by the scientific community. Copyright 1996-2002 by Scientific Instrument Services. All rights reserved. This program or any of its parts may not be reproduced on another site without the concent of Scientific Instrument Services. The Formula can input using the standard one or two letter chemical symbols, number of atoms and parenthesizes where applicable. The same atom can be listed more than once and where no quantity is
Mass Spec Tools
Calculate Isotopes
Chemical Formula:
Calculation Method:
Minimum abundance:
Note: assumes neutral charge.

Plot Configuration
Show Plot
Low Mass: High Mass:
Plot Size: Show Mass Labels
Data table (mass intensity)


This program can calculate the isotopic distribution of a given chemical species. It can also plot either calculated or manually inputted isotopic distributions.

This program has been developed by Scientific Instrument Services as part of the Mass Spec Tools Collection. For a complete description of this program visit the Description of this Program Page. This program is still under development. If you have any comments or suggestions we would like to hear from you.


Key in the chemical formula for which you would like to determine the isotopic distributions. Also type in the titles and the mass scale range which will be present in the final graphical output. You have the option of calculating the masses in low resolution or high resolution.

Example Chemical Formulas:


Calculation should take upwards of a few seconds depending on the size of the chemical species.

The species is assumed neutral (mass of added/removed electrons and binding energy is not taken into account), which can have an affect on the high resolution methods.

These isotopes are supported:


MS Calculator Pro image

Other mass spectra tools

SIS also sells the Mass Spec Calculator Pro™, a standalone Windows application. Unlike the online calculator, you are not as limited to the size of compounds that may be calculated. A demo may be downloaded.

  • Molecular drawing, fragmentation, and autofragmentation
  • Enhanced Isotopic Profile utility based on a completely new algorithm that calculates isotopic mass distributions for a structure.
  • Elemental Formula utility calculates the possible compositions of an ion given its mass.
  • Spectrum Capture utility that can automatically digitize a scanned spectrum and import it for use within MSC.

Isotope distributions can also be calculated using the Isotopes Calculator in the MS Interpreter tool in the NIST Mass Spectral Database.

Developed by John J. Manura and David J. Manura,
© 1996-2014 Scientific Instrument Services.
Scientific Instrument Services is not responsible for any errors which may result from the use of this program.
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