H12 tolerance (hole, IT12)
Hole tolerance class H12 per ISO 286-1:2010: fundamental deviation EI = 0, grade IT12 (100 µm at ≤ 3 mm to 630 µm at 400–500 mm). For an exact size, open the calculator with H12 selected.
- Type
- Hole
- Grade
- IT12
- Tolerance
- 100 … 630 µm
- Fund. deviation
- EI = 0
H12 limits by size range
| Size (mm) | Upper (µm) | Lower (µm) | Ø max (mm) | Ø min (mm) | Upper (mm) | Lower (mm) | Dev. (in) |
|---|---|---|---|---|---|---|---|
| ≤ 3 | +100 | 0 | 3.100 | 3.000 | +0.100 | 0 | +0.00394 / 0 |
| 3 – 6 | +120 | 0 | 6.120 | 6.000 | +0.120 | 0 | +0.00472 / 0 |
| 6 – 10 | +150 | 0 | 10.150 | 10.000 | +0.150 | 0 | +0.00591 / 0 |
| 10 – 14 | +180 | 0 | 14.180 | 14.000 | +0.180 | 0 | +0.00709 / 0 |
| 14 – 18 | +180 | 0 | 18.180 | 18.000 | +0.180 | 0 | +0.00709 / 0 |
| 18 – 24 | +210 | 0 | 24.210 | 24.000 | +0.210 | 0 | +0.00827 / 0 |
| 24 – 30 | +210 | 0 | 30.210 | 30.000 | +0.210 | 0 | +0.00827 / 0 |
| 30 – 40 | +250 | 0 | 40.250 | 40.000 | +0.250 | 0 | +0.00984 / 0 |
| 40 – 50 | +250 | 0 | 50.250 | 50.000 | +0.250 | 0 | +0.00984 / 0 |
| 50 – 65 | +300 | 0 | 65.300 | 65.000 | +0.300 | 0 | +0.01181 / 0 |
| 65 – 80 | +300 | 0 | 80.300 | 80.000 | +0.300 | 0 | +0.01181 / 0 |
| 80 – 100 | +350 | 0 | 100.350 | 100.000 | +0.350 | 0 | +0.01378 / 0 |
| 100 – 120 | +350 | 0 | 120.350 | 120.000 | +0.350 | 0 | +0.01378 / 0 |
| 120 – 140 | +400 | 0 | 140.400 | 140.000 | +0.400 | 0 | +0.01575 / 0 |
| 140 – 160 | +400 | 0 | 160.400 | 160.000 | +0.400 | 0 | +0.01575 / 0 |
| 160 – 180 | +400 | 0 | 180.400 | 180.000 | +0.400 | 0 | +0.01575 / 0 |
| 180 – 200 | +460 | 0 | 200.460 | 200.000 | +0.460 | 0 | +0.01811 / 0 |
| 200 – 225 | +460 | 0 | 225.460 | 225.000 | +0.460 | 0 | +0.01811 / 0 |
| 225 – 250 | +460 | 0 | 250.460 | 250.000 | +0.460 | 0 | +0.01811 / 0 |
| 250 – 280 | +520 | 0 | 280.520 | 280.000 | +0.520 | 0 | +0.02047 / 0 |
| 280 – 315 | +520 | 0 | 315.520 | 315.000 | +0.520 | 0 | +0.02047 / 0 |
| 315 – 355 | +570 | 0 | 355.570 | 355.000 | +0.570 | 0 | +0.02244 / 0 |
| 355 – 400 | +570 | 0 | 400.570 | 400.000 | +0.570 | 0 | +0.02244 / 0 |
| 400 – 450 | +630 | 0 | 450.630 | 450.000 | +0.630 | 0 | +0.02480 / 0 |
| 450 – 500 | +630 | 0 | 500.630 | 500.000 | +0.630 | 0 | +0.02480 / 0 |
Deviations at the upper end of each range (Ø columns use that size); use the calculator for the exact size. — : not defined by ISO 286 for that size. Upper/Lower (mm) and inch columns are shown on wider screens.
About H12
H12 denotes a hole tolerance zone with zero line deviation in the ISO 286 system.
At Ø25 mm H12 is +0.210 / 0 mm, i.e. 25.000 to 25.210 mm.
How the limits are calculated
H12 uses grade IT12 (a standard tolerance of 210 µm at 18–30 mm). Fundamental deviation: EI = 0: the tolerance zone sits entirely above the nominal size, and IT12 sets its width. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.