ISO Fits & Tolerances Calculator
Hole and shaft limits, clearance or interference, and tolerance zones to scale — ISO 286 hole-basis fits.
What it does
Enter a nominal size and pick a preferred fit (H11/c11 to H7/s6) or build your own hole and shaft combination. The calculator returns the upper and lower limits of the hole and shaft, the maximum and minimum clearance (or interference), the fit type, and a to-scale diagram of both tolerance zones about the zero line.
How to use it
- Enter the nominal size in mm (1–120 mm).
- Choose a preferred fit, or set the hole letter and IT grade and the shaft letter and IT grade yourself.
- Read the hole and shaft limits, the clearance or interference, and whether it is a clearance, transition or interference fit.
- Use the step-by-step working to see how the IT grade and fundamental deviation give each limit.
Solve by hand first, then validate
Every result comes with the working, so you can follow the formulas instead of trusting a black box — the same method we teach in our ANSYS Workbench course. Browse more free calculators and references in Resources.
Frequently asked questions
Which standard does it use?
ISO 286-1 and ISO 286-2 standard tolerance grades and fundamental deviations for nominal sizes up to 120 mm. IS 919 is the Indian equivalent. Always confirm critical tolerances against the current standard.
What is the difference between clearance, transition and interference fits?
A clearance fit always leaves a gap between hole and shaft, an interference fit always needs force or heat to assemble, and a transition fit can give either a small clearance or a small interference depending on the actual sizes.
Is it free? Do I need to sign in?
Yes, it's free and needs no sign-in.