Abstract Summary In mass spectrometry-based proteomics, accurate peptide masses improve identifications, alignment and quantitation. Getting the most out of any instrument therefore requires proper calibration. Here, we present a new stand-alone software, mzRecal, for universal automatic recalibration of data from all common mass analyzers using standard open formats and based on physical principles. Availability and implementation mzRecal is implemented in Go and freely available on https://github.com/524D/mzRecal. Supplementary information Supplementary data are available at Bioinformatics online.