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ISO 286 Fit Calculator

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Unit system
Primary result

Clearance fit

Even the tightest dimensional combination retains clearance.

Minimum clearance Cmin: 0.007 mm
Maximum clearance Cmax: 0.041 mm

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Ø25 mm H7/g6
Fit: Clearance fit
Minimum clearance Cmin: 0.007 mm
Maximum clearance Cmax: 0.041 mm

Hole H7

Upper deviation+21 µm
Lower deviation0 µm
Limit sizes25 mm — 25.021 mm
Tolerance-zone midpoint25.011 mm
IT21 µm

Shaft g6

Upper deviation-7 µm
Lower deviation-20 µm
Limit sizes24.98 mm — 24.993 mm
Tolerance-zone midpoint24.987 mm
IT13 µm

Fit result

Minimum clearance Cmin0.007 mm
Maximum clearance Cmax0.041 mm
Minimum interference0 mm
Maximum interference0 mm

Interference-fit estimate

Preliminary elastic estimate — not a complete DIN 7190-1 implementation.

No interference exists for the selected limits; the mechanical calculation is inactive.

Engineering basis

ISO 286 — ISO 286-1:2010 + ISO 286-2:2010 — dimensional tolerance and fit system.

Current implementation: 1–500 mm, IT5–IT11 and only the tolerance positions shown in the selectors.

The interference-fit section is a preliminary elastic model and must not be interpreted as a complete DIN 7190-1 verification.

Optional guidance

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Fit Selection Assistant

Know the function, but not the H7/... fit yet?

Choose the behavior you want. DraftFit loads a hole-basis H7 starting point, then you evaluate the actual clearance or interference numerically.

These are starting points to evaluate, not automatic design recommendations. Function, loading, assembly, materials and manufacturing process determine the final fit.

Common fits & examples
Common fits

Example presets

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Technical notes

  • • ISO 286 defines the dimensional relationship between features of size; it does not by itself validate the mechanical function of an assembly.
  • • Fit selection depends on load, temperature, materials, contact length, surfaces, lubrication and assembly conditions.
  • • A complete DIN 7190 calculation requires geometry, material and stress-state modelling within the scope of the standard.

Engineering report

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Formulas & methodology

  • Hole lower/upper limit = nominal size + hole lower/upper deviation.
  • Shaft lower/upper limit = nominal size + shaft lower/upper deviation.
  • Minimum clearance Cmin = minimum hole − maximum shaft.
  • Maximum clearance Cmax = maximum hole − minimum shaft.
  • Interference is reported as the magnitude of negative clearance where the shaft is larger than the hole.

Engineering basis & standards

  • Tolerance grades and the implemented fundamental-deviation subset are based on ISO 286-1 / ISO 286-2 methodology.
  • The interference-fit mechanics section is a preliminary elastic cylindrical-contact estimator; it is not a complete DIN 7190 implementation.

Assumptions

  • Nominal diameter is within the supported 1–500 mm range.
  • Materials are treated as linear elastic for the preliminary press-fit mechanics.
  • Geometry is idealized as axisymmetric and does not include local weakening from keyways, cross-holes, grooves or shoulders unless explicitly represented.

Warnings / limits

  • Verify the selected tolerance designation against the governing edition of the standard and the drawing requirements.
  • For safety-critical or highly loaded interference fits, perform a dedicated fit/joint calculation including fatigue, temperature, roughness, assembly method and real hub/shaft geometry.
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Related engineering reading

H7/g6 fit explained →Clearance vs transition vs interference →ISO 286 reference →