Your Molecular Formula

List of allowed groups

Apply Gaussian:
Reference version:

(Peak Full Width at Half-Maximum)

Resolution = M / ΔM


JSON Description

This service allows to retrieve information for a specific molecular formula. The molecular formula may include groups, charges, etc. The service can be accessed from Ajax and the server will return a JSON.


You may implement our tools for free on your server at the condition that you provide a link to "".

On your server edit httpd.conf and add the following line:

ProxyPass /chemcalc
You may now download the example file and install it on your server. To download the file just right click on this link and save to your computer. The result of the page is show just bellow. Just enter a monoisotopic mass and click on "Search molecular formula".

Main script code example

The system use prototype.js and the following example code:

<script language="javascript">
  var chemcalcResult;
  function getChemCalcJSON(mf) {
    new Ajax.Request('/chemcalc', {
        method: 'post',  
        parameters: {mf: mf, isotopomers: "jcamp,xy"},
        onSuccess: function(resp) {

Mandatory parameters:

  • mf:: the molecular formula

Optional parameters:

  • isotopomers: specify if we want isotopic distribution in xy or jcamp format. This parameter may contain "xy" or "jcamp".