BIZOMAT MAKEOS · Engineering
Hole and Shaft Clearance Limits
What clearance or interference can occur at the size limits?
Calculate the worst-case diametral clearance range from explicitly supplied hole and shaft limits.
Open the calculatorRuns in your browser. No account needed.
How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Minimum hole diameter | mm | Lower permitted hole size on the current drawing. |
| Maximum hole diameter | mm | Upper permitted hole size on the current drawing. |
| Minimum shaft diameter | mm | Lower permitted shaft size on the current drawing. |
| Maximum shaft diameter | mm | Upper permitted shaft size on the current drawing. |
What each input means
Open an input to see what it is, its units, the worked example and the common mistakes, with a small diagram.
What this means: Minimum hole diameter
- What it is
- The smallest size the hole is allowed to be, from the drawing’s limits or tolerance callout.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.001 mm to 1000000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 20 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Minimum clearance is this size minus the maximum shaft.
- Get it right
- Work out limit sizes from the current drawing; a fit symbol such as H7 needs its table values applied first.
What this means: Maximum hole diameter
- What it is
- The largest size the hole is allowed to be, from the drawing’s limits or tolerance callout.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.001 mm to 1000000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 20.021 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Maximum clearance is this size minus the minimum shaft.
- Get it right
- It must be at least the minimum hole size.
What this means: Minimum shaft diameter
- What it is
- The smallest size the shaft is allowed to be, from the drawing’s limits or tolerance callout.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.001 mm to 1000000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 19.98 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- A smaller minimum shaft increases the maximum clearance.
- Get it right
- Shaft tolerances are often below nominal; check the sign of each deviation.
What this means: Maximum shaft diameter
- What it is
- The largest size the shaft is allowed to be, from the drawing’s limits or tolerance callout.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.001 mm to 1000000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 19.993 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- A larger maximum shaft reduces the minimum clearance, possibly to interference.
- Get it right
- It must be at least the minimum shaft size.
Method and formulas
- Minimum clearance = minimum hole − maximum shaft.
- Maximum clearance = maximum hole − minimum shaft.
- Positive values are clearance; negative values are interference. Example limits give 0.007 to 0.041 mm diametral clearance.
Limitations
- Uses size limits only; no ISO/ANSI fit-class values are embedded.
- Form, position, finish, coatings, compliance and operating temperature may change assembly behaviour.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- limits fits
- interference
- dimensional tolerance
Who it is for
- Mechanical designers
- Inspectors
What you get
- Minimum signed clearance
- Maximum signed clearance
- Size-only classification
Interpreting the result
- Check limit order and assess geometry and thermal conditions before approving the fit.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 628–631. Topic reference; no source tables or recommended settings are reproduced.
- NPL, Fundamental Good Practice in Dimensional Metrology, GPG 80 — https://eprintspublications.npl.co.uk/3360/1/mgpg80.pdf
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