H7/p7 fit — Locational interference

ISO 286 hole-basis interference fit. Enter a nominal size to get the limits.

Nominal size

Unit

Result

Ø25.000 H7/p7Interference fit

	Upper	Lower	Max	Min	Tol.
Hole H7	+0.021	0	25.021	25.000	0.021
Shaft p7	+0.043	+0.022	25.043	25.022	0.021

Max interference: 0.043 mm
Min interference: 0.001 mm
Mean: −0.022 mm

Fit diagram (µm · zero line = nominal)

Hole tolerance zoneShaft tolerance zoneInterference

About H7/p7

Coarser than H7/p6 for interference fits that lock parts against movement and light torque without a key: bushings pressed into castings, locating pins in fixtures. See press fit tolerance for interference by size across the p6–u6 family.

At Ø25 mm the hole H7 measures 0 mm to +0.021 mm and the shaft p7 +0.022 mm to +0.043 mm, giving an interference of 0.001 mm to 0.043 mm.

How the limits are calculated

Hole H7: fundamental deviation EI = 0, standard tolerance IT7 = 21 µm for 18–30 mm. Shaft p7: fundamental deviation ei = 22 µm, IT7 = 21 µm. Clearance = hole − shaft, evaluated at both extremes. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.

H7/p7 limits by size range

Size (mm)	Hole H7	Shaft p7	Clearance min	Clearance max
≤ 3	+0.010 / 0	+0.016 / +0.006	−0.016	+0.004
3 – 6	+0.012 / 0	+0.024 / +0.012	−0.024	0
6 – 10	+0.015 / 0	+0.030 / +0.015	−0.030	0
10 – 18	+0.018 / 0	+0.036 / +0.018	−0.036	0
18 – 30	+0.021 / 0	+0.043 / +0.022	−0.043	−0.001
30 – 50	+0.025 / 0	+0.051 / +0.026	−0.051	−0.001
50 – 80	+0.030 / 0	+0.062 / +0.032	−0.062	−0.002
80 – 120	+0.035 / 0	+0.072 / +0.037	−0.072	−0.002
120 – 180	+0.040 / 0	+0.083 / +0.043	−0.083	−0.003
180 – 250	+0.046 / 0	+0.096 / +0.050	−0.096	−0.004
250 – 315	+0.052 / 0	+0.108 / +0.056	−0.108	−0.004
315 – 400	+0.057 / 0	+0.119 / +0.062	−0.119	−0.005
400 – 500	+0.063 / 0	+0.131 / +0.068	−0.131	−0.005

Deviations in mm at the upper end of each range; negative clearance = interference. Clearance columns are shown on wider screens. Sub-ranges (e.g. 18–24 / 24–30) can differ for r, s, t, u, v, x, y, z — use the calculator for the exact size. “—” means ISO 286 doesn't define this class below that size (e.g. t only starts at 24 mm).

Is H7/p7 a clearance fit?

No — H7/p7 is an interference fit per ISO 286 (see types of fits). At Ø25 mm it gives an interference of 0.001 mm to 0.043 mm mm, depending which parts of the tolerance zones are paired.

What is the H7/p7 tolerance at 25 mm?

At a nominal size of Ø25 mm, H7 allows a hole diameter from 25.000 to 25.021 mm, and p7 allows a shaft diameter from 25.022 to 25.043 mm.