---
type: "fit"
designation: "F8/h7"
hole: "F8"
shaft: "h7"
basis: "shaft"
classification: "clearance"
role: "Close running, shaft basis."
size_count: 13
standard: "ISO 286-1:2010, ISO 286-2:2010"
verified: "August 1, 2026"
url: https://shopmath.org/fits/f8-h7
---

# F8/h7 Fit — ISO 286 Clearance Fit Limits by Nominal Size

F8/h7 is a clearance fit: at 25 mm nominal it gives 20 to 74 µm clearance. Close running, shaft basis. The hole is always larger than the shaft — the parts always assemble with a gap.

- **Designation**: F8/h7
- **Hole tolerance**: F8
- **Shaft tolerance**: h7
- **Basis**: shaft basis
- **Classification**: Clearance fit
- **Typical use**: Close running, shaft basis.
- **Standard**: ISO 286-1:2010, ISO 286-2:2010

## F8/h7 Hole and Shaft Limits by Nominal Size

Limits in millimetres, clearances in micrometres. A negative clearance is interference — the shaft is larger than the hole and assembly needs force, heat or cold.

| Nominal size | Hole min (mm) | Hole max (mm) | Shaft min (mm) | Shaft max (mm) | Min clearance (µm) | Max clearance (µm) | Result |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 5 mm | 5.010 | 5.028 | 4.988 | 5.000 | 10 | 40 | Clearance |
| 6 mm | 6.010 | 6.028 | 5.988 | 6.000 | 10 | 40 | Clearance |
| 8 mm | 8.013 | 8.035 | 7.985 | 8.000 | 13 | 50 | Clearance |
| 10 mm | 10.013 | 10.035 | 9.985 | 10.000 | 13 | 50 | Clearance |
| 12 mm | 12.016 | 12.043 | 11.982 | 12.000 | 16 | 61 | Clearance |
| 16 mm | 16.016 | 16.043 | 15.982 | 16.000 | 16 | 61 | Clearance |
| 20 mm | 20.020 | 20.053 | 19.979 | 20.000 | 20 | 74 | Clearance |
| 25 mm | 25.020 | 25.053 | 24.979 | 25.000 | 20 | 74 | Clearance |
| 30 mm | 30.020 | 30.053 | 29.979 | 30.000 | 20 | 74 | Clearance |
| 40 mm | 40.025 | 40.064 | 39.975 | 40.000 | 25 | 89 | Clearance |
| 50 mm | 50.025 | 50.064 | 49.975 | 50.000 | 25 | 89 | Clearance |
| 80 mm | 80.030 | 80.076 | 79.970 | 80.000 | 30 | 106 | Clearance |
| 100 mm | 100.036 | 100.090 | 99.965 | 100.000 | 36 | 125 | Clearance |

## Sources and Method for the F8/h7 Fit

### F8/h7 limits

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

### Assumptions

- Values are the ISO 286-2 tabulated limits, not the ISO 286-1 formula: the formula deviates from the table by up to 13.26% and is carried only as a validation harness.
- Limits are at 20 °C, the ISO 1 reference temperature. Clearance is the assembled gap before any thermal or load effect.
- 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

## Common Questions About the F8/h7 Fit

### What kind of fit is F8/h7?

F8/h7 is a clearance fit on a shaft basis. The hole is always larger than the shaft — the parts always assemble with a gap. Close running, shaft basis.

### What is the clearance on a 25 mm F8/h7 fit?

At 25 mm nominal, F8/h7 gives 20 to 74 µm clearance. The hole runs 25.020 to 25.053 mm and the shaft 24.979 to 25.000 mm.

### What hole and shaft tolerances make up F8/h7?

F8/h7 pairs a F8 hole with a h7 shaft. On a shaft basis, the shaft carries the zero-deviation member and the other side is moved to set the fit.

## Related pages

- Hole tolerance: [F8 limits by size](https://shopmath.org/fits/f8.md)
- Shaft tolerance: [h7 limits by size](https://shopmath.org/fits/h7-shaft.md)
- All fits and tolerances: [ISO 286 fit reference](https://shopmath.org/fits.md)
- Full grade table: [ISO 286 tolerance chart](https://shopmath.org/charts/iso-tolerances.md)

---

*Source: [ShopMath](https://shopmath.org/fits/f8-h7) — data verified August 1, 2026. Reference data; verify against the governing standard before manufacture.*