H7/n6 fit — Locational transition

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

Nominal size

Unit

Result

Ø25.000 H7/n6Transition fit

	Upper	Lower	Max	Min	Tol.
Hole H7	+0.021	0	25.021	25.000	0.021
Shaft n6	+0.028	+0.015	25.028	25.015	0.013

Max clearance: 0.006 mm
Max interference: 0.028 mm
Mean: −0.011 mm

Fit diagram (µm · zero line = nominal)

Hole tolerance zoneShaft tolerance zoneClearanceInterference

About H7/n6

Firm fit assembled with a press; parts rarely dismantled, e.g. gear rims on hubs, bushes in housings.

At Ø25 mm the hole H7 measures 0 mm to +0.021 mm and the shaft n6 +0.015 mm to +0.028 mm, giving between 0.028 mm interference and 0.006 mm clearance.

How the limits are calculated

Hole H7: fundamental deviation EI = 0, standard tolerance IT7 = 21 µm for 18–30 mm. Shaft n6: fundamental deviation ei = 15 µm, IT6 = 13 µm. Clearance = hole − shaft, evaluated at both extremes. Values per ISO 286-1:2010.

H7/n6 limits by size range

Size (mm)	Hole H7	Shaft n6	Clearance min	Clearance max
≤ 3	+0.010 / 0	+0.010 / +0.004	−0.010	+0.006
3 – 6	+0.012 / 0	+0.016 / +0.008	−0.016	+0.004
6 – 10	+0.015 / 0	+0.019 / +0.010	−0.019	+0.005
10 – 18	+0.018 / 0	+0.023 / +0.012	−0.023	+0.006
18 – 30	+0.021 / 0	+0.028 / +0.015	−0.028	+0.006
30 – 50	+0.025 / 0	+0.033 / +0.017	−0.033	+0.008
50 – 80	+0.030 / 0	+0.039 / +0.020	−0.039	+0.010
80 – 120	+0.035 / 0	+0.045 / +0.023	−0.045	+0.012
120 – 180	+0.040 / 0	+0.052 / +0.027	−0.052	+0.013
180 – 250	+0.046 / 0	+0.060 / +0.031	−0.060	+0.015
250 – 315	+0.052 / 0	+0.066 / +0.034	−0.066	+0.018
315 – 400	+0.057 / 0	+0.073 / +0.037	−0.073	+0.020
400 – 500	+0.063 / 0	+0.080 / +0.040	−0.080	+0.023

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.