Tolerance chart

d9 tolerance (shaft): ISO 286 chart up to 500 mm

d9 is an ISO tolerance class for shafts (external features) under ISO 286. At Ø25 mm it means −65 / −117 µm: the size may lie between 24.883 and 24.935 mm. Below are the deviations for every nominal size up to 500 mm and the fits that use d9.

Updated 2026-10-30 · Basis: ISO 286-1:2010 and ISO 286-2:2010 · irot Erstmuster

d9 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	−20	−45	25
3 – 6	−30	−60	30
6 – 10	−40	−76	36
10 – 18	−50	−93	43
18 – 30	−65	−117	52
30 – 50	−80	−142	62
50 – 80	−100	−174	74
80 – 120	−120	−207	87
120 – 180	−145	−245	100
180 – 250	−170	−285	115
250 – 315	−190	−320	130
315 – 400	−210	−350	140
400 – 500	−230	−385	155

d9 for your nominal size

How d9 is built

An ISO tolerance class is a letter and a number. Capital letters stand for holes, small letters for shafts. The letter d sets the position of the tolerance zone; at Ø25 mm it lies entirely below the nominal size: the shaft is always smaller than nominal. The number 9 is the standard tolerance grade IT9: it sets how wide the zone is – 52 µm at Ø25 mm.

The tolerance grows with the nominal size: 25 µm in the smallest row (0 – 3 mm), 155 µm in the largest (400 – 500 mm). On a drawing the class follows the dimension, as in »Ø25 d9«; the inspection plan turns that into the limits 24.883 and 24.935 mm.

Fits with d9 at Ø25 mm

Hole-basis system: the hole is H, the shaft d9. Clearance in µm; a minus means interference. Sorted from the largest minimum clearance to the largest interference.

Fit	Type	Max. clearance	Min. clearance
H9/d9	clearance fit	169	65
H10/d9	clearance fit	201	65

Frequently asked questions about d9

What does d9 mean?

d9 is an ISO tolerance class for shafts (external features): the letter d sets the position of the tolerance zone, the number 9 the standard tolerance grade IT9. At Ø25 mm that gives −65 / −117 µm, i.e. 24.883 to 24.935 mm.

What are the d9 limits at Ø10 and Ø50 mm?

Ø10 d9: −40 / −76 µm (9.924 to 9.960 mm). Ø50 d9: −80 / −142 µm (49.858 to 49.920 mm).

Is d9 a clearance fit?

A tolerance class on its own is not a fit – only together with its mating part. H10/d9 at Ø25 mm is a clearance fit (maximum clearance 201 µm, minimum clearance 65 µm; a minus means interference).

More tolerance classes

Same letter d, other grades: d10

Shafts in grade 9: h9

All classes at a glance: ISO 286 tolerance charts. The same chart in German: d9 Toleranz.