About ChemCalcAbout ChemCalc: the people behind the molecular formula and mass spectrometry tools, and the publication to cite. Developed since 2001 as part of the open-source cheminfo ecosystem. Please enable JavaScript to use the interactive application.

The ChemCalc toolbox

Molecular formula finder from monoisotopic mass

Compounds for a molecular formula

Peptide and protein fragmentation calculator

Nucleotide and oligonucleotide fragmentation calculator

Polymer mass distribution calculator

Atomic elements and isotope reference table

Chemical group abbreviations

Publications and literature

ChemCalc Web Services and API

ChemCalc documentation

Mass spectrometry exercises

Determine the charge state — mass spectrometry exercises
Find the monoisotopic mass — mass spectrometry exercises
Determine the composition from the isotopic distribution
Determine the molecular formula — mass spectrometry exercises
Match spectra and molecules — electron-impact exercises

ChemCalc news

The ChemCalc newsletter

Cite ChemCalc — Patiny L, Borel A. ChemCalc: a building block for tomorrow's chemical infrastructure. J Chem Inf Model. 2013. DOI: 10.1021/ci300563h

About ChemCalc