Tolerance chart
H11 tolerance (hole): ISO 286 chart up to 500 mm
H11 is an ISO tolerance class for holes (internal features) under ISO 286. At Ø25 mm it means +130 / 0 µm: the size may lie between 25.000 and 25.130 mm. Below are the deviations for every nominal size up to 500 mm and the fits that use H11.
H11 chart: deviations for all nominal sizes up to 500 mm
Deviations in µm (1 µm = 0.001 mm). A nominal size belongs to the row »over … up to and including …«: exactly 30 mm is in the row ending at 30, 30.1 mm in the next one.
| Nominal size over – to (mm) | Upper deviation | Lower deviation | Tolerance |
|---|---|---|---|
| 0 – 3 | +60 | 0 | 60 |
| 3 – 6 | +75 | 0 | 75 |
| 6 – 10 | +90 | 0 | 90 |
| 10 – 18 | +110 | 0 | 110 |
| 18 – 30 | +130 | 0 | 130 |
| 30 – 50 | +160 | 0 | 160 |
| 50 – 80 | +190 | 0 | 190 |
| 80 – 120 | +220 | 0 | 220 |
| 120 – 180 | +250 | 0 | 250 |
| 180 – 250 | +290 | 0 | 290 |
| 250 – 315 | +320 | 0 | 320 |
| 315 – 400 | +360 | 0 | 360 |
| 400 – 500 | +400 | 0 | 400 |
H11 for your nominal size
How H11 is built
An ISO tolerance class is a letter and a number. Capital letters stand for holes, small letters for shafts. The letter H sets the position of the tolerance zone; at Ø25 mm it lies from the nominal size upwards: the hole is never smaller than nominal. The number 11 is the standard tolerance grade IT11: it sets how wide the zone is – 130 µm at Ø25 mm.
The tolerance grows with the nominal size: 60 µm in the smallest row (0 – 3 mm), 400 µm in the largest (400 – 500 mm). On a drawing the class follows the dimension, as in »Ø25 H11«; the inspection plan turns that into the limits 25.000 and 25.130 mm.
Fits with H11 at Ø25 mm
Hole-basis system: the hole stays H11, the shaft changes. Clearance in µm; a minus means interference. Sorted from the largest minimum clearance to the largest interference.
Frequently asked questions about H11
What does H11 mean?
H11 is an ISO tolerance class for holes (internal features): the letter H sets the position of the tolerance zone, the number 11 the standard tolerance grade IT11. At Ø25 mm that gives +130 / 0 µm, i.e. 25.000 to 25.130 mm.
What are the H11 limits at Ø10 and Ø50 mm?
Ø10 H11: +90 / 0 µm (10.000 to 10.090 mm). Ø50 H11: +160 / 0 µm (50.000 to 50.160 mm).
Is H11 a clearance fit?
A tolerance class on its own is not a fit – only together with its mating part. H11/d10 at Ø25 mm is a clearance fit (maximum clearance 279 µm, minimum clearance 65 µm; a minus means interference).
More tolerance classes
Same letter H, other grades: H6 · H7 · H8 · H9 · H10
All classes at a glance: ISO 286 tolerance charts. The same chart in German: H11 Toleranz.