Comparison between direct metallicity estimates (x axis) and indirect metallicity estimates (y axis) obtained using the calibration based on R₃, N₂, O₃N₂ and N₂S₂Hα diagnostics proposed in this work. Data points are divided into PHANGS–MUSE data (dark green points) and all the other data taken from the literature catalogues (light green points). The solid line is the 1:1 relation.