Calculate limit sizes, deviations, minimum clearance, and maximum clearance for holes and shafts.
Compare limit values at the current nominal size. Optionally narrow the results to a desired range in µm.
The calculator determines the limit sizes of two ISO 286 tolerance zones and derives minimum and maximum clearance or interference.
Enter the nominal diameter and the hole (uppercase, for example H7) and shaft (lowercase, for example g6) tolerance fields. The nominal-size range selects the ISO table for fundamental deviation and IT grade.
The diameter selects the ISO size step, which changes IT width and fundamental deviation. Upper- and lowercase letters locate the zones relative to the zero line and determine whether clearance or interference is possible.
Each tolerance field is combined with the nominal size and its upper and lower deviation. Hole limit size minus shaft limit size gives minimum and maximum fit; the sign identifies clearance or interference.
For 40 H7/g6 the hole is between 40.000 and 40.025 mm. The shaft is slightly smaller; the difference between the least favorable limits is the minimum clearance.
Sources and limits: ISO 286-1 defines the tolerance system; ISO 286-2 provides table values. This is a dimensional calculation, not a functional or assembly approval.
The calculator determines the limit sizes of two ISO 286 tolerance zones and derives minimum and maximum clearance or interference.
A tolerance defines the permitted size range of a manufactured feature. Its position locates that range around the zero line, while the IT grade sets its width.
Each tolerance field is combined with the nominal size and its upper and lower deviation. Hole limit size minus shaft limit size gives minimum and maximum fit; the sign identifies clearance or interference.
Enter the nominal diameter and the hole (uppercase, for example H7) and shaft (lowercase, for example g6) tolerance fields. The nominal-size range selects the ISO table for fundamental deviation and IT grade. The diameter selects the ISO size step, which changes IT width and fundamental deviation. Upper- and lowercase letters locate the zones relative to the zero line and determine whether clearance or interference is possible.
Enter the nominal diameter and the tolerance fields of hole and shaft (e.g. H7 for the hole, g6 for the shaft). The calculator returns limit sizes for both parts and the resulting minimum and maximum clearance or interference.
For 40 H7/g6 the hole is between 40.000 and 40.025 mm. The shaft is slightly smaller; the difference between the least favorable limits is the minimum clearance.
The diameter selects the ISO size step, which changes IT width and fundamental deviation. Upper- and lowercase letters locate the zones relative to the zero line and determine whether clearance or interference is possible. Positive clearance means the hole remains larger than the shaft in the least favorable limits. A negative result is interference and needs separate assembly, temperature and joining checks.
Nominal and limit sizes in millimetres, tolerance fields as a letter plus IT grade (e.g. H7).
Checking whether a planned or existing hole-shaft combination actually delivers the intended clearance or interference, for example for bearing seats, guides or shaft-hub connections.
ISO 286-1 defines the tolerance system; ISO 286-2 provides table values. This is a dimensional calculation, not a functional or assembly approval.
Common mistake: Don't confuse hole and shaft letters – uppercase is always a hole, lowercase always a shaft; H7/g6 and h7/G6 describe different parts with swapped tolerance positions. The nominal-size step (e.g. over 18 to 30 mm) also determines the fundamental tolerance; the same letter and grade give different absolute values at a different size step.
A negative value indicates interference: at that limit the shaft is larger than the hole, so the parts would need to be joined with force or a temperature difference.
H7 identifies a hole field with zero lower deviation, while h7 identifies a shaft field with zero upper deviation; both share the same IT7 tolerance width but sit on different sides of the zero line.
No, it is a pure dimensional calculation at the 20 °C reference temperature. Manufacturing scatter, temperature effects and the joint's actual function must be assessed separately.
From nominal size plus hole and shaft tolerance classes, the calculator returns limit sizes and minimum/maximum clearance or interference.
ISO 286 defines hole and shaft sizes. Performance in the actual assembly also depends on temperature, form, surface texture, and assembly conditions.
Differential thermal expansion can turn clearance into interference, or the reverse.
Roundness, cylindricity, and roughness are not controlled by a size fit.
Derive minimum clearance or interference from load, lubrication, and assembly needs.
Geometrical tolerances for form, orientation, location, and run-out.
Unambiguous specification of linear sizes on drawings.
Surface texture specification for sliding, sealing, or joining functions.