ISO fit calculator (hole and shaft tolerances)

Limits for H7/g6, H7/p6 and other ISO 286 fits, with clearance or interference.

ISO 286 builds every fit from a tolerance grade (IT5-IT11 here, wider as the number rises) and a fundamental deviation (the letter: a hole H starts at the nominal size, a shaft g sits just below it, a shaft p just above). Hole-basis fits with H holes are the usual choice because reamers and plug gauges come in H sizes. Values are the ISO 286-1 tables for sizes up to 500 mm.