Exact masses for glycans, glycopeptides & glycoproteins.
Enter a sequence and a glycan composition — get the monoisotopic and most-abundant m/z, the molecular formula, and a fully interactive isotope spectrum. No spreadsheets, no guesswork.
Three engines. One chemistry.
Each calculator shares a single, validated mass model — amino-acid and monosaccharide compositions resolved through the same isotope engine that draws your spectrum.
Glycopeptide
Peptide sequence plus Hex / HexNAc / Fuc / Sia, with carbamidomethylation and deamidation. Returns m/z, formula and isotope spectrum at any charge.
Calculate →Glycoprotein
Full-length sequences with disulfide-bridge corrections and selectable instrument resolution — denatured or natively folded.
Calculate →Free glycan
Released glycans with permethylation, peracetylation, reduced ends and 2-AB / 2-AA labels — plus sodium-adduct handling for positive mode.
Calculate →# request { "hex": 5, "hexnac": 4, "fuc": 1, "sia": 2, "charge": 2, "modification": "none" } # 200 OK { "mono_mz": 1185.4277, "most_abundant_mz": 1185.9292, "composition": "C90 H148 N6 O66 S0", "spectrum": { "mz": […], "intensity": […] } }
The same math, programmatically.
Every calculator is a documented JSON endpoint backed by the exact same core the website uses. Pipe it into your processing scripts, notebooks or LIMS — interactive OpenAPI docs live at /docs.
Built by glycobiologists, for glycobiologists.
GlycoMass began in 2020 as a working bench tool and is being rebuilt in 2026 — same trusted chemistry, modern foundations.
Glycoanalytics
Engineering