What Size Is M18?

What Size Is M18? Tap size Basic major dia (mm) Basic major dia (inch) M16 x 1.5 16mm .6299 M18 x 2.518mm .7087 M18 x 1.5 18mm .7087 M20 x 2.5 20mm .7874 What size is M18 bolt? Diameter (d) Pitch Head Depth (k) M14 2mm 8.8mm M16 2mm 10mm M182.5mm 11.5mm M20 2.5mm 12.5mm