Fits & Clearances Calculator
Enter the size deviations for a hole and shaft pair to get maximum/minimum clearance or interference, and the resulting fit classification.
Enter your values
Deviations from nominal size, in micrometers (µm). Look these up from your ISO fit callout (e.g. H7/g6) or drawing.
How this calculator works
With hole deviations (ES = upper, EI = lower) and shaft deviations (es = upper, ei = lower), all measured from the shared nominal size:
A positive value is clearance (gap); a negative value is interference (overlap, requiring press or shrink fit). If max clearance is positive and min clearance is negative, the fit is a transition fit — it can land as either clearance or interference depending on which in-tolerance parts are actually assembled.
Common ISO fit classes (H-hole basis)
| Fit | Type | Typical use |
|---|---|---|
| H7/g6 | Clearance | Sliding fit, easy to assemble/disassemble |
| H7/h6 | Clearance (locational) | Accurate location, free to slide by hand |
| H7/k6 | Transition | Light press, precise location |
| H7/p6 | Interference | Press fit, permanent assembly |
Look up the ES/EI/es/ei values for your specific size range and fit class from an ISO 286 tolerance table, then enter them above.
Frequently asked questions
Where do I find the deviation values for my fit callout?
Standard ISO 286 tolerance tables (widely published in engineering handbooks and CAD tolerance references) list ES/EI and es/ei in micrometers for each size range and IT grade combination.
Does this calculate the tolerance grade (IT number) itself?
No — this tool works from deviations you already have (from a table or drawing) to find the resulting clearance or interference. It doesn't derive IT grade values from first principles.