What is the clearance of a 25 mm P7/h6 fit?

A 25 mm P7/h6 fit has -35 to -1 µm of clearance: the hole runs 24.965 to 24.986 mm and the shaft 24.987 to 25.000 mm. A negative figure is interference — the parts must be pressed, heated or chilled together.

What is P7/h6 used for?

Locational interference, shaft basis. It is a shaft-basis fit, so the shaft is held to one standard tolerance and the hole is machined to suit.

How does the P7/h6 fit change with size?

Across the 13 verified nominal sizes the clearance runs from -59 µm at 100 mm to 0 µm at 5 mm, because both tolerance bands widen with nominal size.

ISO 286 · interference fit · shaft basis

P7/h6 Interference Fit — Hole and Shaft Limits by Size

https://shopmath.org/fits/p7-h6 · data verified August 1, 2026

A 25 mm P7/h6 fit gives -35 to -1 µm of clearance — a 24.965–24.986 mm hole on a 24.987–25.000 mm shaft. Locational interference, shaft basis. The shaft is always larger than the hole — assembly needs force, heat or cold. All values apply at 20 °C.

Type: interference
Hole: P7
Shaft: h6
Sizes: 13
Standard: ISO 286-1:2010

P7/h6 at Ø25 mm · clearance, µm

-35 … -1

Hole: 24.965–24.986mm
Shaft: 24.987–25.000mm

Negative is interference. At Ø25 mm this joint is 35 µm interference at worst case — an assembly force, not a slip fit.

P7/h6 Fit — Hole and Shaft Limits with Clearance, by Nominal Size

Both parts' limits in millimetres and the resulting clearance in micrometres. Negative clearance is interference: the shaft is larger than the hole and the joint needs force, heat or cold to assemble.

P7/h6 fit — hole limits, shaft limits and clearance by nominal size
Property	Hole, mm		Shaft, mm		Clearance, µm		Property
Nominal Ø	Min	Max	Min	Max	Min	Max	At this size
5 mm	4.980	4.992	4.992	5.000	-20	0	interference
6 mm	5.980	5.992	5.992	6.000	-20	0	interference
8 mm	7.976	7.991	7.991	8.000	-24	0	interference
10 mm	9.976	9.991	9.991	10.000	-24	0	interference
12 mm	11.971	11.989	11.989	12.000	-29	0	interference
16 mm	15.971	15.989	15.989	16.000	-29	0	interference
20 mm	19.965	19.986	19.987	20.000	-35	-1	interference
25 mm	24.965	24.986	24.987	25.000	-35	-1	interference
30 mm	29.965	29.986	29.987	30.000	-35	-1	interference
40 mm	39.958	39.983	39.984	40.000	-42	-1	interference
50 mm	49.958	49.983	49.984	50.000	-42	-1	interference
80 mm	79.949	79.979	79.981	80.000	-51	-2	interference
100 mm	99.941	99.976	99.978	100.000	-59	-2	interference

Minimum clearance is the largest shaft in the smallest hole; maximum clearance is the smallest shaft in the largest hole. Values apply at the ISO 286 reference temperature of 20 °C.

The Hole and Shaft Tolerances That Make the P7/h6 Fit

P7/h6 is P7 on the hole and h6 on the shaft. It is a shaft-basis fit: the shaft is held to one standard tolerance and the hole is varied — which is what you want when the shaft is a drawn or ground bar bought to size.

Hole
P7 →
Shaft-basis light interference hole.
Shaft
h6 →
Precision basic shaft — zero upper deviation, the reference for locational clearance fits.

Fits That Share a Tolerance With the P7/h6 Fit

Changing one half of the pair is how a design moves from clearance to interference. These fits keep P7 or h6 and change the other side.

ISO 286 fits sharing a hole or shaft tolerance with P7/h6
Fit	Type	What it is for
G7/h6	clearance	Sliding, shaft basis. The h6 shaft is the reference and the hole carries the clearance.
H7/h6	clearance	Locational clearance. Assembles by hand, no free movement intended.
K7/h6	transition	Locational transition, shaft basis.
N7/h6	transition	Tight transition, shaft basis.

Ordered loosest to tightest within each type.

Sources and Method for the P7/h6 Fit Data

P7/h6 limitscomputed

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.

Formula

Clearance from the two tolerance bands

max clearance  =  hole max − shaft min
min clearance  =  hole min − shaft max

A negative result is interference. Both are computed from the compiled ISO 286-2 deviations, not from the ISO 286-1 formula, which deviates from the published table by up to 13%.

Assumptions

Values apply at the ISO 286 reference temperature of 20 °C. A joint assembled hot or cold, or running hot, is not at these limits.
The tolerances cover size only. Form, roundness, cylindricity and surface finish all affect how a fit behaves and 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 P7/h6 Fit Reference

Citation

ShopMath. "P7/h6 Interference Fit — Hole and Shaft Limits by Size." ShopMath, verified August 1, 2026, https://shopmath.org/fits/p7-h6

BibTeX

@misc{shopmath-fits-p7-h6,
  title        = {P7/h6 Interference Fit — Hole and Shaft Limits by Size},
  author       = {{ShopMath}},
  year         = {2026},
  howpublished = {\url{https://shopmath.org/fits/p7-h6}},
  note         = {Data verified 2026-08-01}
}

Permanent URL

https://shopmath.org/fits/p7-h6

Common Questions About the P7/h6 Fit

What is the clearance of a 25 mm P7/h6 fit?: A 25 mm P7/h6 fit has -35 to -1 µm of clearance: the hole runs 24.965 to 24.986 mm and the shaft 24.987 to 25.000 mm. A negative figure is interference — the parts must be pressed, heated or chilled together.
Is P7/h6 a clearance, transition or interference fit?: P7/h6 is a interference fit. The shaft is always larger than the hole — assembly needs force, heat or cold. Locational interference, shaft basis.
What is P7/h6 used for?: Locational interference, shaft basis. It is a shaft-basis fit, so the shaft is held to one standard tolerance and the hole is machined to suit.
How does the P7/h6 fit change with size?: Across the 13 verified nominal sizes the clearance runs from -59 µm at 100 mm to 0 µm at 5 mm, because both tolerance bands widen with nominal size.

Every ISO 286 designation and fit · ISO 286 tolerance chart