RandoziHole and Shaft Clearance Calculator
Type the hole and the shaft with their tolerances and read the nominal gap, the smallest and the largest gap, and whether the fit always leaves a clearance, always interferes, or can do either.
Gap, hole minus shaft (mm)
0.05 to 0.35
Clearance guaranteed · nominal gap 0.2
Sizes only. Roundness, position, finish, temperature and 3D-print shrinkage are not included, so a fit can still fail in practice.
How it works
- Enter the nominal size of the hole and its plus and minus tolerances (positive amounts).
- Enter the nominal size of the shaft and its tolerances the same way.
- Read the smallest and largest gap and the type of fit.
- Copy the result, or change a tolerance to see how the range moves.
What people use it for
Choosing a pin and a bore
Check that a 10 mm pin always enters a 10.2 mm hole once both are within tolerance.
3D printing and machining
Compare the hole you print or drill with the shaft you bought, using the tolerances you measured or were given.
Checking a drawing
Confirm by hand what a fit on a drawing allows at its two extremes.
Questions
- What are the formulas?
- Gap = hole − shaft. The smallest gap is the smallest hole minus the largest shaft; the largest gap is the largest hole minus the smallest shaft. If the smallest gap is above 0 the fit always has a clearance; if the largest gap is below 0 it always interferes; otherwise it can be either.
- Does it use ISO fit codes like H7/g6?
- No. You type the actual limits, so you can read them off any table or drawing. The page does not look up codes, to avoid giving a number it cannot source for your size.
- What does it leave out?
- Roundness, straightness, position, surface finish, temperature and the way a 3D printer shrinks a hole. It compares sizes only, so a fit can still fail in practice.
- What if the smallest gap is exactly 0?
- Then the parts can just touch with no room, so the fit is shown as mixed: it is not guaranteed to leave a clearance.