H7 tolerance (hole, IT7)
Hole tolerance class H7 per ISO 286-1:2010: fundamental deviation EI = 0, grade IT7 (10 µm at ≤ 3 mm to 63 µm at 400–500 mm). For an exact size, open the calculator with H7 selected.
- Type
- Hole
- Grade
- IT7
- Tolerance
- 10 … 63 µm
- Fund. deviation
- EI = 0
H7 limits by size range
| Size (mm) | Upper (µm) | Lower (µm) | Ø max (mm) | Ø min (mm) | Upper (mm) | Lower (mm) | Dev. (in) |
|---|---|---|---|---|---|---|---|
| ≤ 3 | +10 | 0 | 3.010 | 3.000 | +0.010 | 0 | +0.00039 / 0 |
| 3 – 6 | +12 | 0 | 6.012 | 6.000 | +0.012 | 0 | +0.00047 / 0 |
| 6 – 10 | +15 | 0 | 10.015 | 10.000 | +0.015 | 0 | +0.00059 / 0 |
| 10 – 14 | +18 | 0 | 14.018 | 14.000 | +0.018 | 0 | +0.00071 / 0 |
| 14 – 18 | +18 | 0 | 18.018 | 18.000 | +0.018 | 0 | +0.00071 / 0 |
| 18 – 24 | +21 | 0 | 24.021 | 24.000 | +0.021 | 0 | +0.00083 / 0 |
| 24 – 30 | +21 | 0 | 30.021 | 30.000 | +0.021 | 0 | +0.00083 / 0 |
| 30 – 40 | +25 | 0 | 40.025 | 40.000 | +0.025 | 0 | +0.00098 / 0 |
| 40 – 50 | +25 | 0 | 50.025 | 50.000 | +0.025 | 0 | +0.00098 / 0 |
| 50 – 65 | +30 | 0 | 65.030 | 65.000 | +0.030 | 0 | +0.00118 / 0 |
| 65 – 80 | +30 | 0 | 80.030 | 80.000 | +0.030 | 0 | +0.00118 / 0 |
| 80 – 100 | +35 | 0 | 100.035 | 100.000 | +0.035 | 0 | +0.00138 / 0 |
| 100 – 120 | +35 | 0 | 120.035 | 120.000 | +0.035 | 0 | +0.00138 / 0 |
| 120 – 140 | +40 | 0 | 140.040 | 140.000 | +0.040 | 0 | +0.00157 / 0 |
| 140 – 160 | +40 | 0 | 160.040 | 160.000 | +0.040 | 0 | +0.00157 / 0 |
| 160 – 180 | +40 | 0 | 180.040 | 180.000 | +0.040 | 0 | +0.00157 / 0 |
| 180 – 200 | +46 | 0 | 200.046 | 200.000 | +0.046 | 0 | +0.00181 / 0 |
| 200 – 225 | +46 | 0 | 225.046 | 225.000 | +0.046 | 0 | +0.00181 / 0 |
| 225 – 250 | +46 | 0 | 250.046 | 250.000 | +0.046 | 0 | +0.00181 / 0 |
| 250 – 280 | +52 | 0 | 280.052 | 280.000 | +0.052 | 0 | +0.00205 / 0 |
| 280 – 315 | +52 | 0 | 315.052 | 315.000 | +0.052 | 0 | +0.00205 / 0 |
| 315 – 355 | +57 | 0 | 355.057 | 355.000 | +0.057 | 0 | +0.00224 / 0 |
| 355 – 400 | +57 | 0 | 400.057 | 400.000 | +0.057 | 0 | +0.00224 / 0 |
| 400 – 450 | +63 | 0 | 450.063 | 450.000 | +0.063 | 0 | +0.00248 / 0 |
| 450 – 500 | +63 | 0 | 500.063 | 500.000 | +0.063 | 0 | +0.00248 / 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 H7
H7 denotes a hole tolerance zone with zero line deviation in the ISO 286 system. It is used in H7/f7 (Sliding parts and journals at moderate speeds with noticeable but small play.) and H7/g6 (Precision sliding parts that must move without perceptible play: spindles, sliding gears, guide pins, plungers.).
At Ø25 mm H7 is +0.021 / 0 mm, i.e. 25.000 to 25.021 mm.
How the limits are calculated
H7 uses grade IT7 (a standard tolerance of 21 µm at 18–30 mm). Fundamental deviation: EI = 0: the tolerance zone sits entirely above the nominal size, and IT7 sets its width. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.