M–Z relation for the PG16S calibration used throughout this work. The DustPedia sample is divided in LTG (green) and ETG (magenta). The HIGH (blue), HAPLESS (cyan), and DGS (purple) samples are added to improve statistics at the low-metallicity end. Additionally, we show the best-fit M–Z relations (third order polynomials) for the different metallicity calibrations listed in Table 5. The y-axis offset for the various calibrations differs substantially, though the overall shape is similar.