We use the most homogeneous Geneva seven-colour photometric system to derive new metallicity calibrations for early A- to K-type stars that cover both,
dwarf stars and giants. The calibrations are based on several spectroscopic data sets that were merged to a common scale, and we applied them to open
cluster data to obtain an additional proof of the metallicity scale and accuracy. In total, metallicities of 54 open clusters are presented. The accuracy
of the calibrations for single stars is in general below 0.1 dex, but for the open cluster sample with mean values based on several stars we find a much
better precision, a scatter as low as about 0.03 dex. Furthermore, we combine the new results with another comprehensive photometric data set to present
a catalogue of mean metallicities for more than 3000 F- and G-type dwarf stars with σ ∼ 0.06 dex. The list was extended by more than 1200 hotter
stars up to about 8500 K (or spectral type A3) by taking advantage of their almost reddening free characteristic in the new Geneva metallicity calibrations.
These two large samples are well suited as primary or secondary calibrators of other data, and we already identified about 20 spectroscopic data sets that
show offsets up to about 0.4 dex.