What is the tolerance of a 25 mm p6 shaft?

A 25 mm p6 shaft runs 25.022 to 25.035 mm — deviations of +22 to +35 µm, a tolerance band 13 µm wide.

p6 is an ISO 286 shaft tolerance. The p sets the fundamental deviation — light interference — and the 6 is the IT6 tolerance grade, which sets how wide the band is. Light interference shaft for locational press fits in steel.

How wide is the IT6 tolerance band?

IT6 is 13 µm wide for nominal sizes over 18 up to 30 mm, and widens with size — the full band table is on this page.

p6 appears in 1 standard ISO 286 fits: H7/p6 (interference).

Is there a p6 page for each nominal size?

Yes — p6 carries a page for each of the thirteen nominal sizes with verified demand, from 5 mm to 100 mm, each with the limits, the IT grades at that size and the fits available there.

ISO 286 · shaft tolerance · IT6

p6 Tolerance — Shaft Limits by Nominal Size

https://shopmath.org/fits/p6 · data verified August 1, 2026

A 25 mm p6 shaft runs 25.022 to 25.035 mm — deviations of +22 to +35 µm on a tolerance band 13 µm wide. The p sets where the band sits (light interference) and IT6 sets how wide it is. Light interference shaft for locational press fits in steel. All values apply at 20 °C.

Feature: shaft
Letter: p
Grade: IT6
Sizes: 13
Standard: ISO 286-1:2010

p6 shaft at Ø25 mm · deviation, µm

+35 / +22

Max Ø: 25.035mm
Min Ø: 25.022mm
Band: 13µm

Deviations from the 25 mm nominal size, at 20 °C. Every other verified size is in the table below.

Source: ISO 286-1:2010, ISO 286-2:2010
Formula: max Ø = nominal + es min Ø = nominal + ei
Assumptions: Ø25 mm nominal, 18–30 mm size step, plain cylindrical feature, 20 °C. Deviations are tabulated in the standard and compiled here; the limits are those deviations added to the nominal size.
Verified: August 1, 2026

p6 Shaft Limits at Every Verified Nominal Size

Deviations in micrometres and finished limits in millimetres. Every size links to its own page.

p6 shaft tolerance — deviations and limits by nominal size
Property	Deviation, µm		Limits, mm		Property
Nominal Ø	Upper	Lower	Min	Max	Tolerance band, µm
5 mm	+20	+12	5.012	5.020	8
6 mm	+20	+12	6.012	6.020	8
8 mm	+24	+15	8.015	8.024	9
10 mm	+24	+15	10.015	10.024	9
12 mm	+29	+18	12.018	12.029	11
16 mm	+29	+18	16.018	16.029	11
20 mm	+35	+22	20.022	20.035	13
25 mm	+35	+22	25.022	25.035	13
30 mm	+35	+22	30.022	30.035	13
40 mm	+42	+26	40.026	40.042	16
50 mm	+42	+26	50.026	50.042	16
80 mm	+51	+32	80.032	80.051	19
100 mm	+59	+37	100.037	100.059	22

Deviations are relative to the nominal size: positive is above it, negative below. Limits assume the ISO 286 reference temperature of 20 °C.

The IT6 Tolerance Grade in p6, Across ISO 286 Size Bands

The number in p6 is the IT grade, and it sets how wide the tolerance band is. The band widens with size — that is the whole point of a graded tolerance system.

IT6 standard tolerance by nominal size band
Nominal size band	Tolerance, µm	Tolerance, mm
over 0 to 3 mm	6	0.006
over 3 to 6 mm	8	0.008
over 6 to 10 mm	9	0.009
over 10 to 18 mm	11	0.011
over 18 to 30 mm	13	0.013
over 30 to 50 mm	16	0.016
over 50 to 80 mm	19	0.019
over 80 to 120 mm	22	0.022
over 120 to 180 mm	25	0.025
over 180 to 250 mm	29	0.029
over 250 to 315 mm	32	0.032
over 315 to 400 mm	36	0.036
over 400 to 500 mm	40	0.040

Bands are open at the bottom and closed at the top: 'over 18 to 30 mm' includes 30 mm and excludes 18 mm.

Fundamental Deviation of the p shaft Tolerance in p6

The letter in p6 sets where the tolerance band sits relative to the nominal size: light interference. The grade then adds the band width to that starting point.

Fundamental deviation of p (shaft) by nominal size band
Nominal size band	Fundamental deviation, µm	Which limit it sets
over 3 to 6 mm	+12	lower (ei / EI)
over 6 to 10 mm	+15	lower (ei / EI)
over 10 to 18 mm	+18	lower (ei / EI)
over 18 to 30 mm	+22	lower (ei / EI)
over 30 to 40 mm	+26	lower (ei / EI)
over 40 to 50 mm	+26	lower (ei / EI)
over 50 to 65 mm	+32	lower (ei / EI)
over 65 to 80 mm	+32	lower (ei / EI)
over 80 to 100 mm	+37	lower (ei / EI)
over 100 to 120 mm	+37	lower (ei / EI)
over 120 to 140 mm	+43	lower (ei / EI)
over 140 to 160 mm	+43	lower (ei / EI)
over 160 to 180 mm	+43	lower (ei / EI)
over 180 to 200 mm	+50	lower (ei / EI)
over 200 to 225 mm	+50	lower (ei / EI)
over 225 to 250 mm	+50	lower (ei / EI)
over 250 to 280 mm	+56	lower (ei / EI)
over 280 to 315 mm	+56	lower (ei / EI)
over 315 to 355 mm	+62	lower (ei / EI)
over 355 to 400 mm	+62	lower (ei / EI)

The fundamental deviation is the limit nearest the nominal size. For a hole it is the lower limit for letters A–H and the upper limit above that; the other limit follows from the IT grade.

Standard Fits That Use the p6 Tolerance

A tolerance on its own is half a fit. These are the standard ISO 286 pairs p6 appears in, with what each one is used for.

Standard ISO 286 fits that use p6
Fit	Type	Basis	What it is for
H7/p6	interference	hole basis	Locational interference. Rigid location in steel without the load capacity of a drive fit.

Clearance, transition and interference are properties of the pair, not of either tolerance alone.

Sources and Method for the p6 Tolerance Data

p6 limitscomputed

limits computed from the compiled ISO 286 tables: ISO 286-1 IT grades and ISO 286-2 fundamental deviations, compiled from saucecode/ISO286 (LGPL-2.1) and parkergreene/isofits (MIT), cross-checked cell-for-cell

Verified against parkergreene/isofits ISO 286-2 limit tables (MIT); ISO 286-1 formula harness — 2067 checks passed

Computed from the standard's formulas, then checked against published tables.

IT6 tolerance gradecompiled

ISO 286-1 IT grades and ISO 286-2 fundamental deviations, compiled from saucecode/ISO286 (LGPL-2.1) and parkergreene/isofits (MIT), cross-checked cell-for-cell

Verified against parkergreene/isofits ISO 286-2 limit tables (MIT); ISO 286-1 formula harness — 2067 checks passed. Formula per ISO 286-1 standard tolerance factor and fundamental deviation formulas, used as a validation harness only per docs/research/data-sourcing.md §3.6

Compiled from independent public sources that agree cell-for-cell.

p fundamental deviationcompiled

ISO 286-1 IT grades and ISO 286-2 fundamental deviations, compiled from saucecode/ISO286 (LGPL-2.1) and parkergreene/isofits (MIT), cross-checked cell-for-cell

Verified against parkergreene/isofits ISO 286-2 limit tables (MIT); ISO 286-1 formula harness — 2067 checks passed

Compiled from independent public sources that agree cell-for-cell.

Formula

Limits from the deviations, shaft tolerance

max Ø  =  nominal + es
min Ø  =  nominal + ei

  es = upper deviation (µm)
  ei = lower deviation (µm)

The deviations are tabulated in ISO 286-2 and compiled here; the limits are those deviations added to the nominal size, which is why both columns are shown.

Assumptions

Values apply at the ISO 286 reference temperature of 20 °C.
Limits are for a plain cylindrical feature. A tolerance letter says nothing about surface finish, form or roundness — those need their own callouts.
Dataset scope: COMPILED not computed: the ISO 286-1 formula deviates up to 13.26% from the table and is used only as a harness (warn >5%, fail >15%). EXCLUDED: shaft/hole letters s, t, u and the fits H7/s6, H7/t6, H7/u6 — no free source and an undetermined step constant in the formula.

Data last verified

August 1, 2026

How this data is built and checked →

How to Cite This p6 Tolerance Reference

Citation

ShopMath. "p6 Tolerance — Shaft Limits by Nominal Size." ShopMath, verified August 1, 2026, https://shopmath.org/fits/p6

BibTeX

@misc{shopmath-fits-p6,
  title        = {p6 Tolerance — Shaft Limits by Nominal Size},
  author       = {{ShopMath}},
  year         = {2026},
  howpublished = {\url{https://shopmath.org/fits/p6}},
  note         = {Data verified 2026-08-01}
}

Permanent URL

https://shopmath.org/fits/p6

Common Questions About the p6 Tolerance

What is the tolerance of a 25 mm p6 shaft?: A 25 mm p6 shaft runs 25.022 to 25.035 mm — deviations of +22 to +35 µm, a tolerance band 13 µm wide.
What does p6 mean?: p6 is an ISO 286 shaft tolerance. The p sets the fundamental deviation — light interference — and the 6 is the IT6 tolerance grade, which sets how wide the band is. Light interference shaft for locational press fits in steel.
How wide is the IT6 tolerance band?: IT6 is 13 µm wide for nominal sizes over 18 up to 30 mm, and widens with size — the full band table is on this page.
Which fits use p6?: p6 appears in 1 standard ISO 286 fits: H7/p6 (interference).
Is there a p6 page for each nominal size?: Yes — p6 carries a page for each of the thirteen nominal sizes with verified demand, from 5 mm to 100 mm, each with the limits, the IT grades at that size and the fits available there.

Every ISO 286 designation and fit · ISO 286 tolerance chart