H6 tolerance (hole, IT6)
Hole tolerance class H6 per ISO 286-1:2010: fundamental deviation EI = 0, grade IT6 (6 µm at ≤ 3 mm to 40 µm at 400–500 mm). For an exact size, open the calculator with H6 selected.
- Type
- Hole
- Grade
- IT6
- Tolerance
- 6 … 40 µm
- Fund. deviation
- EI = 0
H6 limits by size range
| Size (mm) | Upper (µm) | Lower (µm) | Ø max (mm) | Ø min (mm) | Upper (mm) | Lower (mm) | Dev. (in) |
|---|---|---|---|---|---|---|---|
| ≤ 3 | +6 | 0 | 3.006 | 3.000 | +0.006 | 0 | +0.00024 / 0 |
| 3 – 6 | +8 | 0 | 6.008 | 6.000 | +0.008 | 0 | +0.00031 / 0 |
| 6 – 10 | +9 | 0 | 10.009 | 10.000 | +0.009 | 0 | +0.00035 / 0 |
| 10 – 14 | +11 | 0 | 14.011 | 14.000 | +0.011 | 0 | +0.00043 / 0 |
| 14 – 18 | +11 | 0 | 18.011 | 18.000 | +0.011 | 0 | +0.00043 / 0 |
| 18 – 24 | +13 | 0 | 24.013 | 24.000 | +0.013 | 0 | +0.00051 / 0 |
| 24 – 30 | +13 | 0 | 30.013 | 30.000 | +0.013 | 0 | +0.00051 / 0 |
| 30 – 40 | +16 | 0 | 40.016 | 40.000 | +0.016 | 0 | +0.00063 / 0 |
| 40 – 50 | +16 | 0 | 50.016 | 50.000 | +0.016 | 0 | +0.00063 / 0 |
| 50 – 65 | +19 | 0 | 65.019 | 65.000 | +0.019 | 0 | +0.00075 / 0 |
| 65 – 80 | +19 | 0 | 80.019 | 80.000 | +0.019 | 0 | +0.00075 / 0 |
| 80 – 100 | +22 | 0 | 100.022 | 100.000 | +0.022 | 0 | +0.00087 / 0 |
| 100 – 120 | +22 | 0 | 120.022 | 120.000 | +0.022 | 0 | +0.00087 / 0 |
| 120 – 140 | +25 | 0 | 140.025 | 140.000 | +0.025 | 0 | +0.00098 / 0 |
| 140 – 160 | +25 | 0 | 160.025 | 160.000 | +0.025 | 0 | +0.00098 / 0 |
| 160 – 180 | +25 | 0 | 180.025 | 180.000 | +0.025 | 0 | +0.00098 / 0 |
| 180 – 200 | +29 | 0 | 200.029 | 200.000 | +0.029 | 0 | +0.00114 / 0 |
| 200 – 225 | +29 | 0 | 225.029 | 225.000 | +0.029 | 0 | +0.00114 / 0 |
| 225 – 250 | +29 | 0 | 250.029 | 250.000 | +0.029 | 0 | +0.00114 / 0 |
| 250 – 280 | +32 | 0 | 280.032 | 280.000 | +0.032 | 0 | +0.00126 / 0 |
| 280 – 315 | +32 | 0 | 315.032 | 315.000 | +0.032 | 0 | +0.00126 / 0 |
| 315 – 355 | +36 | 0 | 355.036 | 355.000 | +0.036 | 0 | +0.00142 / 0 |
| 355 – 400 | +36 | 0 | 400.036 | 400.000 | +0.036 | 0 | +0.00142 / 0 |
| 400 – 450 | +40 | 0 | 450.040 | 450.000 | +0.040 | 0 | +0.00157 / 0 |
| 450 – 500 | +40 | 0 | 500.040 | 500.000 | +0.040 | 0 | +0.00157 / 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 H6
H6 denotes a hole tolerance zone with zero line deviation in the ISO 286 system. It is used in H6/g5 (High-precision sliding parts with minimum play: measuring instrument spindles, precision guide pins.) and H6/h5 (Precision parts located by the fit alone and assembled by hand, e.g. gauges and instrument components.).
At Ø25 mm H6 is +0.013 / 0 mm, i.e. 25.000 to 25.013 mm.
How the limits are calculated
H6 uses grade IT6 (a standard tolerance of 13 µm at 18–30 mm). Fundamental deviation: EI = 0: the tolerance zone sits entirely above the nominal size, and IT6 sets its width. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.