Engineering Tool

Fit & Tolerance Calculator

Calculate interference and clearance for shaft and housing fits. Select tolerance grades per ISO 286 and GB/T 307.

Input

Bearing dimensions and tolerance grades.

Bore diameter (d) mm

Outer diameter (D) mm

Shaft tolerance inner ring fit

Housing tolerance outer ring fit

Range: d 3–120mm, D 6–120mm. Bearing tolerance = normal grade P0 (GB/T 307.1).

Enter dimensions to calculate fits.

Recommended Fits by Application

General motors (inner ring rotating)

Shaft: k6 / Housing: H7

Most common combination. Light interference on inner ring prevents creep; clearance on outer ring eases assembly and thermal compensation.

Heavy loads / shock loads

Shaft: m6 or n6 / Housing: K7

Heavier interference needed to prevent inner ring from slipping on the shaft under high loads.

Stationary inner ring / non-rotating load

Shaft: g6 or h6 / Housing: H7

Inner ring can be looser for easier disassembly and axial adjustment.

High temperature operation

Shaft: k6 / Housing: H7 + C3/C4 clearance

Temperature differential reduces interference. Consider upsizing shaft fit and selecting larger internal clearance (C3/C4).

Standards used: ISO 286 / GB/T 1800.1-2020 (IT6/IT7 tolerances, shaft deviations g/h/js/k/m/n/p). Bearing bore and outer diameter tolerances per GB/T 307.1 normal grade (P0). Results show maximum and minimum interference (positive = tight) or clearance (negative = loose).