What is the clearance of a 25 mm H7/h6 fit?

A 25 mm H7/h6 fit has 0 to +34 µm of clearance: the hole runs 25.000 to 25.021 mm and the shaft 24.987 to 25.000 mm.

Is H7/h6 a clearance, transition or interference fit?

H7/h6 is a clearance fit. The hole is always larger than the shaft — the parts always assemble with a gap. Locational clearance. Assembles by hand, no free movement intended.

What is H7/h6 used for?

Locational clearance. Assembles by hand, no free movement intended. It works on either basis.

How does the H7/h6 fit change with size?

Across the 13 verified nominal sizes the clearance runs from 0 µm at 5 mm to +57 µm at 100 mm, because both tolerance bands widen with nominal size.

ISO 286 · clearance fit · hole or shaft basis

H7/h6 Clearance Fit — Hole and Shaft Limits by Size

https://shopmath.org/fits/h7-h6 · data verified August 1, 2026

A 25 mm H7/h6 fit gives 0 to +34 µm of clearance — a 25.000–25.021 mm hole on a 24.987–25.000 mm shaft. Locational clearance. Assembles by hand, no free movement intended. The hole is always larger than the shaft — the parts always assemble with a gap. All values apply at 20 °C.

Type: clearance
Hole: H7
Shaft: h6
Sizes: 13
Standard: ISO 286-1:2010

H7/h6 at Ø25 mm · clearance, µm

0 … +34

Hole: 25.000–25.021mm
Shaft: 24.987–25.000mm

Clearance at Ø25 mm, at 20 °C. Every other verified size is in the table below.

H7/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.

H7/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	5.000	5.012	4.992	5.000	0	+20	clearance
6 mm	6.000	6.012	5.992	6.000	0	+20	clearance
8 mm	8.000	8.015	7.991	8.000	0	+24	clearance
10 mm	10.000	10.015	9.991	10.000	0	+24	clearance
12 mm	12.000	12.018	11.989	12.000	0	+29	clearance
16 mm	16.000	16.018	15.989	16.000	0	+29	clearance
20 mm	20.000	20.021	19.987	20.000	0	+34	clearance
25 mm	25.000	25.021	24.987	25.000	0	+34	clearance
30 mm	30.000	30.021	29.987	30.000	0	+34	clearance
40 mm	40.000	40.025	39.984	40.000	0	+41	clearance
50 mm	50.000	50.025	49.984	50.000	0	+41	clearance
80 mm	80.000	80.030	79.981	80.000	0	+49	clearance
100 mm	100.000	100.035	99.978	100.000	0	+57	clearance

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 H7/h6 Fit

H7/h6 is H7 on the hole and h6 on the shaft. It works on either basis: both members are zero-deviation tolerances.

Hole
H7 →
The default basic hole in hole-basis fitting — reamer and gauge sizes are built around it.
Shaft
h6 →
Precision basic shaft — zero upper deviation, the reference for locational clearance fits.

Fits That Share a Tolerance With the H7/h6 Fit

Changing one half of the pair is how a design moves from clearance to interference. These fits keep H7 or h6 and change the other side.

ISO 286 fits sharing a hole or shaft tolerance with H7/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/g6	clearance	Sliding. Locates accurately, still moves and turns freely.
H7/p6	interference	Locational interference. Rigid location in steel without the load capacity of a drive fit.
H7/r6	interference	Medium drive. The joint itself carries load.
P7/h6	interference	Locational interference, shaft basis.
H7/k6	transition	Locational transition. Accurate location, assembles with light force.
H7/m6	transition	Locational transition, tighter than k6.
H7/n6	transition	Tight transition. Usually a press job.
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 H7/h6 Fit Data

H7/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 H7/h6 Fit Reference

Citation

ShopMath. "H7/h6 Clearance Fit — Hole and Shaft Limits by Size." ShopMath, verified August 1, 2026, https://shopmath.org/fits/h7-h6

BibTeX

@misc{shopmath-fits-h7-h6,
  title        = {H7/h6 Clearance Fit — Hole and Shaft Limits by Size},
  author       = {{ShopMath}},
  year         = {2026},
  howpublished = {\url{https://shopmath.org/fits/h7-h6}},
  note         = {Data verified 2026-08-01}
}

Permanent URL

https://shopmath.org/fits/h7-h6

Common Questions About the H7/h6 Fit

What is the clearance of a 25 mm H7/h6 fit?: A 25 mm H7/h6 fit has 0 to +34 µm of clearance: the hole runs 25.000 to 25.021 mm and the shaft 24.987 to 25.000 mm.
Is H7/h6 a clearance, transition or interference fit?: H7/h6 is a clearance fit. The hole is always larger than the shaft — the parts always assemble with a gap. Locational clearance. Assembles by hand, no free movement intended.
What is H7/h6 used for?: Locational clearance. Assembles by hand, no free movement intended. It works on either basis.
How does the H7/h6 fit change with size?: Across the 13 verified nominal sizes the clearance runs from 0 µm at 5 mm to +57 µm at 100 mm, because both tolerance bands widen with nominal size.

Every ISO 286 designation and fit · ISO 286 tolerance chart