Tolerances & Fits
Calculator
Enter a nominal size and pick a hole and a shaft tolerance class to see the limit deviations and the resulting clearance or interference.
Hole tolerance class
IT5 to IT9 · deviations E to USwipe sideways for more →Shaft tolerance class
IT5 to IT9 · deviations e to uValues per ISO 286-1 and ISO 286-2. Hole classes E to U and shaft classes e to u, tolerance grades IT5 to IT9, nominal sizes up to 500 mm.
Results are provided for guidance. Always confirm critical tolerances against the current standard and your drawing.
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Reading the result
Hole basis and shaft basis
In the hole basis system the hole is fixed at H (lower deviation zero) and the shaft letter sets the fit. In the shaft basis system the shaft is fixed at h. Hole basis is the usual choice because reamers and plug gauges come in standard sizes.
Clearance, transition, interference
Clearance is the hole size minus the shaft size. A clearance fit is always positive, an interference fit always negative, and a transition fit can be either, depending on the actual parts.
Letters and numbers
In a class such as H7 or g6, the letter fixes where the tolerance zone sits relative to the nominal size, and the number is the IT grade, which sets how wide the zone is.