Molecular formula from exact mass
Candidate formulas for a measured m/z, with mass error in ppm, RDBE and a plausibility score.
No sign-up. The result appears immediately.
Exact mass alone rarely determines a molecular formula. The calculator returns every candidate inside the tolerance window and scores them additionally by ring and double bond equivalents and by how common the elemental composition is.
Keep going on the whole molecule
This calculator shows one slice. With a free account you compute spectra, stability, toxicology and synthesis routes on the same molecule, in the browser or in Claude and ChatGPT.