Shaft/Hole Tolerance
Compute upper/lower deviations and limit sizes at a nominal size for a given IT grade and shaft('h')/hole('H') tolerance basis.
Inputs
Formula
i = 0.45·∛D + 0.001D (µm); IT = k(grade)·i; shaft h: es=0, ei=−IT; hole H: EI=0, ES=+IT
IT5–IT12 supported; shaft basis h (upper dev 0), hole basis H (lower dev 0).
Fundamentals
Shaft tolerance is the allowed variation of shaft size; with hole tolerance it sets fit looseness (clearance, transition or interference).
Fit is set by the relative position of hole/shaft tolerance zones: hole max − shaft min gives max clearance, shaft max − hole min gives interference. Hole-basis (hole = H) is most common for tooling standardisation.
History
The limits-and-fits system was proposed by Taylor (1905); ISO 286 (1970s) unified tolerance grades and the base system.
Engineering applications
Used for interchangeable precision fits such as motor-shaft/bearing, piston/cylinder and gear-bore/shaft.
Glossary
| Tolerance zone | Size region between upper and lower deviations. |
| Hole basis | Fit system with hole basic deviation H. |
| Fit | General term for how loose/tight hole and shaft join. |
How to use
- Fill in Nominal D, IT grade, Basis in the Inputs section (watch the unit on each field).
- Click Calculate; the tool evaluates the formula shown above.
- Read Tolerance IT, Upper dev., Lower dev., Max limit, Min limit in the results area.
Formula notesTolerance grade IT sets the standard tolerance; clearance = hole_max − shaft_min, interference = hole_min − shaft_max.
Formula · Worked Example · Knowledge
Formula
Standard tolerance unit $i=0.45\sqrt[3]{D}+0.001D$ (µm), IT=k(grade)·i; shaft h basis es=0, ei=−IT; hole H basis EI=0, ES=+IT.
Worked Example
D=50 mm, IT7 (k=16) → i≈1.56 µm, IT≈25 µm; shaft h7: es=0, ei=−25 µm.
Key Points
- IT5–IT12 supported; larger size → larger unit.
- Clearance/interference comes from hole+shaft deviations.
- Fit choice balances assembly and motion needs.
Parameters
Inputs
| Parameter | Symbol | Unit | Default |
|---|---|---|---|
| Nominal D (mm) | D | mm | 50 |
| IT grade | grade | 7 | |
| Basis | basis | shaft |
Outputs
| Result | Symbol | Unit |
|---|---|---|
| Tolerance IT | IT | µm |
| Upper dev. | upper | µm |
| Lower dev. | lower | µm |
| Max limit | dmax | mm |
| Min limit | dmin | mm |
Applications
- Common engineering use cases
FAQ
What formula does this tool use?
This tool computes per ISO / AGMA / ASME standard formulas: i = 0.45·∛D + 0.001D (µm); IT = k(grade)·i; shaft h: es=0, ei=−IT; hole H: EI=0, ES=+IT
How accurate are the results?
Results match input precision, based on SI units and common engineering approximations; for critical duty re-check with a safety factor.
Where is it used?
Common engineering use cases