Tolerance and fit

Use limits or signed deviations consistently

A deviation is an offset from nominal size, not an absolute dimension. Keep its sign when entering an upper or lower deviation. This tool applies the limits you provide; it does not look up every standardized hole and shaft tolerance class.

Dimensional fit is only part of assembly behavior

Temperature, surface finish, roundness, alignment, and coatings can affect the assembled parts. The endpoint range is useful for checking a drawing or comparing proposed tolerances, but it does not predict insertion force, contact pressure, lubrication performance, or the probability of a particular clearance.

Calculating endpoints instead of nominal clearance

Suppose the hole may range from 10.00 to 10.02 mm and the shaft from 9.98 to 9.99 mm. Minimum clearance is 10.00 minus 9.99, or 0.01 mm. Maximum clearance is 10.02 minus 9.98, or 0.04 mm. Subtracting nominal sizes alone would not show the full permitted range or establish whether every allowed pair assembles with clearance.

For a transition fit, the interval crosses zero, so both clearance and interference are possible within the dimensional limits. The calculator describes endpoints, not the probability of either outcome. That probability would require information about the manufacturing distributions and their relationship. Check whether tolerances are bilateral, unilateral, or given directly as limits before entering them. Coatings and temperature can shift effective dimensions after inspection. A clearance range also does not specify lubrication, alignment, running accuracy, or insertion force. Use the dimensional result to verify the intended fit, then assess those functional requirements separately.

Formula

Minimum clearance = smallest hole − largest shaft. Maximum clearance = largest hole − smallest shaft.