cationCalc4EPMA: A MATLAB-based open-source tool for reproducible cation calculations from EPMA datasets

Electron probe microanalysis (EPMA) provides precise chemical compositions of minerals, but transforming oxide weight percentages into cation-based formulas remains a critical and often irreproducible step in petrological workflows. We present cationCalc4EPMA, an open-source MATLAB tool that converts EPMA datasets into cation-normalized structural formulas with automatic mineral identification. The software supports major rock-forming minerals, implements established stoichiometric and charge-balance schemes for Fe³⁺ estimation, and computes commonly used petrological indices such as Mg#. By replacing spreadsheet-based or proprietary workflows, cationCalc4EPMA enhances transparency, reproducibility, and efficiency in geochemical and petrological studies using EPMA data.