T7 tolerance (hole, IT7)
Hole tolerance class T7 per ISO 286-1:2010: fundamental deviation ES −33 … −337, grade IT7 (10 µm at ≤ 3 mm to 63 µm at 400–500 mm). For an exact size, open the calculator with T7 selected.
- Type
- Hole
- Grade
- IT7
- Tolerance
- 10 … 63 µm
- Fund. deviation
- ES −33 … −337 µm
T7 limits by size range
| Size (mm) | Upper (µm) | Lower (µm) | Ø max (mm) | Ø min (mm) | Upper (mm) | Lower (mm) | Dev. (in) |
|---|---|---|---|---|---|---|---|
| ≤ 3 | — | — | — | — | — | — | — |
| 3 – 6 | — | — | — | — | — | — | — |
| 6 – 10 | — | — | — | — | — | — | — |
| 10 – 14 | — | — | — | — | — | — | — |
| 14 – 18 | — | — | — | — | — | — | — |
| 18 – 24 | — | — | — | — | — | — | — |
| 24 – 30 | −33 | −54 | 29.967 | 29.946 | −0.033 | −0.054 | −0.00130 / −0.00213 |
| 30 – 40 | −39 | −64 | 39.961 | 39.936 | −0.039 | −0.064 | −0.00154 / −0.00252 |
| 40 – 50 | −45 | −70 | 49.955 | 49.930 | −0.045 | −0.070 | −0.00177 / −0.00276 |
| 50 – 65 | −55 | −85 | 64.945 | 64.915 | −0.055 | −0.085 | −0.00217 / −0.00335 |
| 65 – 80 | −64 | −94 | 79.936 | 79.906 | −0.064 | −0.094 | −0.00252 / −0.00370 |
| 80 – 100 | −78 | −113 | 99.922 | 99.887 | −0.078 | −0.113 | −0.00307 / −0.00445 |
| 100 – 120 | −91 | −126 | 119.909 | 119.874 | −0.091 | −0.126 | −0.00358 / −0.00496 |
| 120 – 140 | −107 | −147 | 139.893 | 139.853 | −0.107 | −0.147 | −0.00421 / −0.00579 |
| 140 – 160 | −119 | −159 | 159.881 | 159.841 | −0.119 | −0.159 | −0.00469 / −0.00626 |
| 160 – 180 | −131 | −171 | 179.869 | 179.829 | −0.131 | −0.171 | −0.00516 / −0.00673 |
| 180 – 200 | −149 | −195 | 199.851 | 199.805 | −0.149 | −0.195 | −0.00587 / −0.00768 |
| 200 – 225 | −163 | −209 | 224.837 | 224.791 | −0.163 | −0.209 | −0.00642 / −0.00823 |
| 225 – 250 | −179 | −225 | 249.821 | 249.775 | −0.179 | −0.225 | −0.00705 / −0.00886 |
| 250 – 280 | −198 | −250 | 279.802 | 279.750 | −0.198 | −0.250 | −0.00780 / −0.00984 |
| 280 – 315 | −220 | −272 | 314.780 | 314.728 | −0.220 | −0.272 | −0.00866 / −0.01071 |
| 315 – 355 | −247 | −304 | 354.753 | 354.696 | −0.247 | −0.304 | −0.00972 / −0.01197 |
| 355 – 400 | −273 | −330 | 399.727 | 399.670 | −0.273 | −0.330 | −0.01075 / −0.01299 |
| 400 – 450 | −307 | −370 | 449.693 | 449.630 | −0.307 | −0.370 | −0.01209 / −0.01457 |
| 450 – 500 | −337 | −400 | 499.663 | 499.600 | −0.337 | −0.400 | −0.01327 / −0.01575 |
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 T7
T7 denotes a hole tolerance zone with heavy interference deviation in the ISO 286 system.
At Ø25 mm T7 is −0.033 / −0.054 mm, i.e. 24.946 to 24.967 mm.
How the limits are calculated
T7 uses grade IT7 (a standard tolerance of 21 µm at 18–30 mm). Fundamental deviation: ES = −ei + Δ (Δ = ITn − IT(n−1), applied up to IT8 for K/M/N and IT7 otherwise); IT7 sets the width below ES. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.