Free mass spectrometry software can be found at www.wsearch.com.au
Wsearch is a windows program that is used to display mass spectral data that has been acquired on any of a number of commercial mass spectrometry instruments. It supports a large number of file formats and also two mass spectral library formats. Currently there are four versions.
Tools (Some mass spec tools I created) Free to use at your own risk.
Molecular weight calculator
Molecular Weight Calculator.zip
Elemental composition Calculator.
Elemental Composition Calculator.zip