H11/a11 fit — Very loose fit
ISO 286 hole-basis clearance fit. Enter a nominal size to get the limits.
Result
| Upper | Lower | Max | Min | Tol. | |
|---|---|---|---|---|---|
| Hole H11 | +0.130 | 0 | 25.130 | 25.000 | |
| Shaft a11 | −0.300 | −0.430 | 24.700 | 24.570 |
- Max clearance
- 0.560 mm
- Min clearance
- 0.300 mm
- Mean
- +0.430 mm
Fit diagram (µm · zero line = nominal)
About H11/a11
Maximum clearance in the standard series; used where parts run hot or where accuracy is irrelevant.
At Ø25 mm the hole H11 measures 0 mm to +0.130 mm and the shaft a11 −0.430 mm to −0.300 mm, giving a clearance of 0.300 mm to 0.560 mm.
How the limits are calculated
Hole H11: fundamental deviation EI = 0, standard tolerance IT11 = 130 µm for 18–30 mm. Shaft a11: fundamental deviation es = -300 µm, IT11 = 130 µm. Clearance = hole − shaft, evaluated at both extremes. Values per ISO 286-1:2010.
H11/a11 limits by size range
| Size (mm) | Hole H11 | Shaft a11 | Clearance min | Clearance max |
|---|---|---|---|---|
| ≤ 3 | +0.060 / 0 | −0.270 / −0.330 | +0.270 | +0.390 |
| 3 – 6 | +0.075 / 0 | −0.270 / −0.345 | +0.270 | +0.420 |
| 6 – 10 | +0.090 / 0 | −0.280 / −0.370 | +0.280 | +0.460 |
| 10 – 18 | +0.110 / 0 | −0.290 / −0.400 | +0.290 | +0.510 |
| 18 – 30 | +0.130 / 0 | −0.300 / −0.430 | +0.300 | +0.560 |
| 30 – 50 | +0.160 / 0 | −0.320 / −0.480 | +0.320 | +0.640 |
| 50 – 80 | +0.190 / 0 | −0.360 / −0.550 | +0.360 | +0.740 |
| 80 – 120 | +0.220 / 0 | −0.410 / −0.630 | +0.410 | +0.850 |
| 120 – 180 | +0.250 / 0 | −0.580 / −0.830 | +0.580 | +1.080 |
| 180 – 250 | +0.290 / 0 | −0.820 / −1.110 | +0.820 | +1.400 |
| 250 – 315 | +0.320 / 0 | −1.050 / −1.370 | +1.050 | +1.690 |
| 315 – 400 | +0.360 / 0 | −1.350 / −1.710 | +1.350 | +2.070 |
| 400 – 500 | +0.400 / 0 | −1.650 / −2.050 | +1.650 | +2.450 |
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.