H7/h6 fit — Locational clearance
ISO 286 hole-basis clearance fit. Enter a nominal size to get the limits.
About H7/h6
Precisely located parts that can still be assembled and turned by hand: gears on shafts fixed by keys, pulleys, centring flanges.
At Ø25 mm the hole H7 measures 0 mm to +0.021 mm and the shaft h6 −0.013 mm to 0 mm, giving a clearance of 0.000 mm to 0.034 mm.
How the limits are calculated
Hole H7: fundamental deviation EI = 0, standard tolerance IT7 = 21 µm for 18–30 mm. Shaft h6: fundamental deviation es = 0, IT6 = 13 µm. Clearance = hole − shaft, evaluated at both extremes. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.
H7/h6 limits by size range
| Size (mm) | Hole H7 | Shaft h6 | Clearance min | Clearance max |
|---|---|---|---|---|
| ≤ 3 | +0.010 / 0 | 0 / −0.006 | 0 | +0.016 |
| 3 – 6 | +0.012 / 0 | 0 / −0.008 | 0 | +0.020 |
| 6 – 10 | +0.015 / 0 | 0 / −0.009 | 0 | +0.024 |
| 10 – 18 | +0.018 / 0 | 0 / −0.011 | 0 | +0.029 |
| 18 – 30 | +0.021 / 0 | 0 / −0.013 | 0 | +0.034 |
| 30 – 50 | +0.025 / 0 | 0 / −0.016 | 0 | +0.041 |
| 50 – 80 | +0.030 / 0 | 0 / −0.019 | 0 | +0.049 |
| 80 – 120 | +0.035 / 0 | 0 / −0.022 | 0 | +0.057 |
| 120 – 180 | +0.040 / 0 | 0 / −0.025 | 0 | +0.065 |
| 180 – 250 | +0.046 / 0 | 0 / −0.029 | 0 | +0.075 |
| 250 – 315 | +0.052 / 0 | 0 / −0.032 | 0 | +0.084 |
| 315 – 400 | +0.057 / 0 | 0 / −0.036 | 0 | +0.093 |
| 400 – 500 | +0.063 / 0 | 0 / −0.040 | 0 | +0.103 |
Deviations in mm at the upper end of each range; negative clearance = interference. Clearance columns are shown on wider screens. Sub-ranges (e.g. 18–24 / 24–30) can differ for r, s, t, u, v, x, y, z — use the calculator for the exact size. “—” means ISO 286 doesn't define this class below that size (e.g. t only starts at 24 mm).
Is H7/h6 a clearance fit?
Yes — H7/h6 is a clearance fit per ISO 286 (see types of fits). At Ø25 mm it gives a clearance of 0.000 mm to 0.034 mm mm, depending which parts of the tolerance zones are paired.
What is the H7/h6 tolerance at 25 mm?
At a nominal size of Ø25 mm, H7 allows a hole diameter from 25.000 to 25.021 mm, and h6 allows a shaft diameter from 24.987 to 25.000 mm.