D8 tolerance (hole, IT8)
Hole tolerance class D8 per ISO 286-1:2010: fundamental deviation EI +20 … +230, grade IT8 (14 µm at ≤ 3 mm to 97 µm at 400–500 mm). For an exact size, open the calculator with D8 selected.
- Type
- Hole
- Grade
- IT8
- Tolerance
- 14 … 97 µm
- Fund. deviation
- EI +20 … +230 µm
D8 limits by size range
| Size (mm) | Upper (µm) | Lower (µm) | Ø max (mm) | Ø min (mm) | Upper (mm) | Lower (mm) | Dev. (in) |
|---|---|---|---|---|---|---|---|
| ≤ 3 | +34 | +20 | 3.034 | 3.020 | +0.034 | +0.020 | +0.00134 / +0.00079 |
| 3 – 6 | +48 | +30 | 6.048 | 6.030 | +0.048 | +0.030 | +0.00189 / +0.00118 |
| 6 – 10 | +62 | +40 | 10.062 | 10.040 | +0.062 | +0.040 | +0.00244 / +0.00157 |
| 10 – 14 | +77 | +50 | 14.077 | 14.050 | +0.077 | +0.050 | +0.00303 / +0.00197 |
| 14 – 18 | +77 | +50 | 18.077 | 18.050 | +0.077 | +0.050 | +0.00303 / +0.00197 |
| 18 – 24 | +98 | +65 | 24.098 | 24.065 | +0.098 | +0.065 | +0.00386 / +0.00256 |
| 24 – 30 | +98 | +65 | 30.098 | 30.065 | +0.098 | +0.065 | +0.00386 / +0.00256 |
| 30 – 40 | +119 | +80 | 40.119 | 40.080 | +0.119 | +0.080 | +0.00469 / +0.00315 |
| 40 – 50 | +119 | +80 | 50.119 | 50.080 | +0.119 | +0.080 | +0.00469 / +0.00315 |
| 50 – 65 | +146 | +100 | 65.146 | 65.100 | +0.146 | +0.100 | +0.00575 / +0.00394 |
| 65 – 80 | +146 | +100 | 80.146 | 80.100 | +0.146 | +0.100 | +0.00575 / +0.00394 |
| 80 – 100 | +174 | +120 | 100.174 | 100.120 | +0.174 | +0.120 | +0.00685 / +0.00472 |
| 100 – 120 | +174 | +120 | 120.174 | 120.120 | +0.174 | +0.120 | +0.00685 / +0.00472 |
| 120 – 140 | +208 | +145 | 140.208 | 140.145 | +0.208 | +0.145 | +0.00819 / +0.00571 |
| 140 – 160 | +208 | +145 | 160.208 | 160.145 | +0.208 | +0.145 | +0.00819 / +0.00571 |
| 160 – 180 | +208 | +145 | 180.208 | 180.145 | +0.208 | +0.145 | +0.00819 / +0.00571 |
| 180 – 200 | +242 | +170 | 200.242 | 200.170 | +0.242 | +0.170 | +0.00953 / +0.00669 |
| 200 – 225 | +242 | +170 | 225.242 | 225.170 | +0.242 | +0.170 | +0.00953 / +0.00669 |
| 225 – 250 | +242 | +170 | 250.242 | 250.170 | +0.242 | +0.170 | +0.00953 / +0.00669 |
| 250 – 280 | +271 | +190 | 280.271 | 280.190 | +0.271 | +0.190 | +0.01067 / +0.00748 |
| 280 – 315 | +271 | +190 | 315.271 | 315.190 | +0.271 | +0.190 | +0.01067 / +0.00748 |
| 315 – 355 | +299 | +210 | 355.299 | 355.210 | +0.299 | +0.210 | +0.01177 / +0.00827 |
| 355 – 400 | +299 | +210 | 400.299 | 400.210 | +0.299 | +0.210 | +0.01177 / +0.00827 |
| 400 – 450 | +327 | +230 | 450.327 | 450.230 | +0.327 | +0.230 | +0.01287 / +0.00906 |
| 450 – 500 | +327 | +230 | 500.327 | 500.230 | +0.327 | +0.230 | +0.01287 / +0.00906 |
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 D8
D8 denotes a hole tolerance zone with running clearance deviation in the ISO 286 system.
At Ø25 mm D8 is +0.098 / +0.065 mm, i.e. 25.065 to 25.098 mm.
How the limits are calculated
D8 uses grade IT8 (a standard tolerance of 33 µm at 18–30 mm). Fundamental deviation: EI = −es of the same shaft letter; IT8 sets the width above EI. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.