h13 shaft tolerance (IT13)
Lower-case h13 is an ISO 286 shaft tolerance class (IT13, es = 0): at Ø10 mm the deviations are 0/−0.220 mm, at Ø25 mm 0/−0.330 mm (upper/lower). Looking for the H13 hole?
Shaft tolerance class h13 per ISO 286-1:2010: fundamental deviation es = 0, grade IT13 (140 µm at ≤ 3 mm to 970 µm at 400–500 mm). For an exact size, open the calculator with h13 selected.
- Type
- Shaft
- Grade
- IT13
- Tolerance
- 140 … 970 µm
- Fund. deviation
- es = 0
h13 limits by size range
| Size (mm) | Upper (µm) | Lower (µm) | Ø max (mm) | Ø min (mm) | Upper (mm) | Lower (mm) | Dev. (in) |
|---|---|---|---|---|---|---|---|
| ≤ 3 | 0 | −140 | 3.000 | 2.860 | 0 | −0.140 | 0 / −0.00551 |
| 3 – 6 | 0 | −180 | 6.000 | 5.820 | 0 | −0.180 | 0 / −0.00709 |
| 6 – 10 | 0 | −220 | 10.000 | 9.780 | 0 | −0.220 | 0 / −0.00866 |
| 10 – 14 | 0 | −270 | 14.000 | 13.730 | 0 | −0.270 | 0 / −0.01063 |
| 14 – 18 | 0 | −270 | 18.000 | 17.730 | 0 | −0.270 | 0 / −0.01063 |
| 18 – 24 | 0 | −330 | 24.000 | 23.670 | 0 | −0.330 | 0 / −0.01299 |
| 24 – 30 | 0 | −330 | 30.000 | 29.670 | 0 | −0.330 | 0 / −0.01299 |
| 30 – 40 | 0 | −390 | 40.000 | 39.610 | 0 | −0.390 | 0 / −0.01535 |
| 40 – 50 | 0 | −390 | 50.000 | 49.610 | 0 | −0.390 | 0 / −0.01535 |
| 50 – 65 | 0 | −460 | 65.000 | 64.540 | 0 | −0.460 | 0 / −0.01811 |
| 65 – 80 | 0 | −460 | 80.000 | 79.540 | 0 | −0.460 | 0 / −0.01811 |
| 80 – 100 | 0 | −540 | 100.000 | 99.460 | 0 | −0.540 | 0 / −0.02126 |
| 100 – 120 | 0 | −540 | 120.000 | 119.460 | 0 | −0.540 | 0 / −0.02126 |
| 120 – 140 | 0 | −630 | 140.000 | 139.370 | 0 | −0.630 | 0 / −0.02480 |
| 140 – 160 | 0 | −630 | 160.000 | 159.370 | 0 | −0.630 | 0 / −0.02480 |
| 160 – 180 | 0 | −630 | 180.000 | 179.370 | 0 | −0.630 | 0 / −0.02480 |
| 180 – 200 | 0 | −720 | 200.000 | 199.280 | 0 | −0.720 | 0 / −0.02835 |
| 200 – 225 | 0 | −720 | 225.000 | 224.280 | 0 | −0.720 | 0 / −0.02835 |
| 225 – 250 | 0 | −720 | 250.000 | 249.280 | 0 | −0.720 | 0 / −0.02835 |
| 250 – 280 | 0 | −810 | 280.000 | 279.190 | 0 | −0.810 | 0 / −0.03189 |
| 280 – 315 | 0 | −810 | 315.000 | 314.190 | 0 | −0.810 | 0 / −0.03189 |
| 315 – 355 | 0 | −890 | 355.000 | 354.110 | 0 | −0.890 | 0 / −0.03504 |
| 355 – 400 | 0 | −890 | 400.000 | 399.110 | 0 | −0.890 | 0 / −0.03504 |
| 400 – 450 | 0 | −970 | 450.000 | 449.030 | 0 | −0.970 | 0 / −0.03819 |
| 450 – 500 | 0 | −970 | 500.000 | 499.030 | 0 | −0.970 | 0 / −0.03819 |
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 h13
h13 denotes a shaft tolerance zone with zero line deviation in the ISO 286 system.
At Ø25 mm h13 is 0 / −0.330 mm, i.e. 24.670 to 25.000 mm.
How the limits are calculated
h13 uses grade IT13 (a standard tolerance of 330 µm at 18–30 mm). Fundamental deviation: es = 0: the tolerance zone sits entirely below the nominal size, and IT13 sets its width. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.
h13 in practice
Where it's used
h13 is the coarsest shaft class most drawings use for diameters: as-turned features, sheet-metal and plastic parts, handles, covers and outside diameters with no function. It says 'no larger than nominal, and not much smaller', which is often all a feature needs. The band is wide enough that a single roughing pass usually meets it, and bright drawn bar stock (typically h9 to h11) meets it as supplied.
How to check it
A caliper is all it needs. Check the largest diameter, because the upper limit is the nominal size itself: a part that is even slightly oversize fails, however generous the lower side is. On turned parts made from bright bar, only the diameters that were actually machined are worth measuring.
Easily confused with
H13 in capitals is the hole class. IT13 is about 1.6 times IT12, so h13 is one step looser than h12. h13 is sometimes written where the designer just meant 'general tolerance'. If the feature has no function, leaving it to ISO 2768 keeps one more callout off the drawing and out of inspection.
Worked example
At Ø20 mm, h13 is 0/−0.330 mm: anything from 19.670 to 20.000 mm passes. A Ø20 bright bar drawn to h11 (19.870–20.000 mm) already sits inside that band as supplied.