M3 screw and bolt sizes for the more common ones we deal with. This will give information about the maximum screw head heights and head diameters as well as the driver size needed to install or remove them. If unfamiliar with DIN and ISO numbers, they can be thought of as exact fastener names for each specific screw and are usually given as either DIN or ISO (eg. DIN 912 or ISO 7380).M3 Screw Size Specs.

Metric M3-0.50, Coarse Thread 

Type DIN ISO

Head Height

Head Diameter Drive Size
M3 Hex Bolts (FT) 933 4017 2.125mm 6.0mm* 5.5mm
M3 Hex Bolts (PT) 931 4014 2.125mm 6.0mm* 5.5mm
M3 Socket Head Cap 912 4762 3.0mm 5.68mm 2.5mm
M3 Low Head Socket Cap 7984 N/A 2.0mm 5.5mm 2mm
M3 Button Head Cap 9427 7380 1.65mm 5.7mm 2mm
M3 Flat Head Socket Cap 7991 10642 1.86mm 6.7mm 2mm
M3 Phil '+' Flat Head 965   1.65mm 5.6mm #1 Phil
M3 Phil '+' Pan Head 7985 7045 2.52mm 6.0mm #1 Phil

All of these will take a matching M3 Nut and Washer
Note: PT / FT = Partial Thread / Full Thread

* 'Width Across Flats' measurement given