H8/e8 fit — Easy running fit
ISO 286 hole-basis clearance fit. Enter a nominal size to get the limits.
About H8/e8
Plain bearings in gearboxes and pumps, sliding gears, easily assembled couplings.
At Ø25 mm the hole H8 measures 0 mm to +0.033 mm and the shaft e8 −0.073 mm to −0.040 mm, giving a clearance of 0.040 mm to 0.106 mm.
How the limits are calculated
Hole H8: fundamental deviation EI = 0, standard tolerance IT8 = 33 µm for 18–30 mm. Shaft e8: fundamental deviation es = -40 µm, IT8 = 33 µm. Clearance = hole − shaft, evaluated at both extremes. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.
H8/e8 limits by size range
| Size (mm) | Hole H8 | Shaft e8 | Clearance min | Clearance max |
|---|---|---|---|---|
| ≤ 3 | +0.014 / 0 | −0.014 / −0.028 | +0.014 | +0.042 |
| 3 – 6 | +0.018 / 0 | −0.020 / −0.038 | +0.020 | +0.056 |
| 6 – 10 | +0.022 / 0 | −0.025 / −0.047 | +0.025 | +0.069 |
| 10 – 18 | +0.027 / 0 | −0.032 / −0.059 | +0.032 | +0.086 |
| 18 – 30 | +0.033 / 0 | −0.040 / −0.073 | +0.040 | +0.106 |
| 30 – 50 | +0.039 / 0 | −0.050 / −0.089 | +0.050 | +0.128 |
| 50 – 80 | +0.046 / 0 | −0.060 / −0.106 | +0.060 | +0.152 |
| 80 – 120 | +0.054 / 0 | −0.072 / −0.126 | +0.072 | +0.180 |
| 120 – 180 | +0.063 / 0 | −0.085 / −0.148 | +0.085 | +0.211 |
| 180 – 250 | +0.072 / 0 | −0.100 / −0.172 | +0.100 | +0.244 |
| 250 – 315 | +0.081 / 0 | −0.110 / −0.191 | +0.110 | +0.272 |
| 315 – 400 | +0.089 / 0 | −0.125 / −0.214 | +0.125 | +0.303 |
| 400 – 500 | +0.097 / 0 | −0.135 / −0.232 | +0.135 | +0.329 |
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 H8/e8 a clearance fit?
Yes — H8/e8 is a clearance fit per ISO 286 (see types of fits). At Ø25 mm it gives a clearance of 0.040 mm to 0.106 mm mm, depending which parts of the tolerance zones are paired.
What is the H8/e8 tolerance at 25 mm?
At a nominal size of Ø25 mm, H8 allows a hole diameter from 25.000 to 25.033 mm, and e8 allows a shaft diameter from 24.927 to 24.960 mm.