ISO 286 Tolerance & ISO 1302 Surface Finish Calculator
Free tolerance lookup for IT5-IT18 grades (0-500 mm), shaft/hole deviation, common fits (H7/g6, H7/h6, H7/p6), and ISO 1302 surface roughness (Ra / Rz / Ry) conversion. For mechanical engineers, CNC machinists, and quality inspectors.
IT Grade Tolerance Size → IT → Tolerance
ISO 286-1:2010 standard tolerance grades. Enter nominal size (mm) and IT grade. The tool returns the tolerance value (in micrometers) and the size range used.
Enter a size and select IT grade.
Shaft/Hole Deviation Position & Grade → es/ei/ES/EI
Returns the upper/lower deviation (es/ei for shaft, ES/EI for hole) per ISO 286-1. For fits like H7/h6, K7/h6, m7/h6, etc.
Enter a size and select a position-grade.
Fit Calculator Hole + Shaft → Fit Type & Limits
Calculates the fit between a hole and shaft per ISO 286-1. Returns clearance/interference range and fit classification.
Select a hole and shaft code to see the fit analysis.
Common Fits (ISO 286-1)
| Fit Code | Type | Application |
|---|
Surface Finish Ra ↔ Rz ↔ Ry
Convert between Ra, Rz, Ry per ISO 1302 (approximate ratios: Rz ≈ 4×Ra, Ry ≈ 6×Ra).
Surface Grade Reference
| ISO Grade | Ra (μm) | Rz (μm) | Typical Process |
|---|
Process Recommendations Manufacturing Process → IT & Ra
Typical achievable IT grade and surface finish for common manufacturing processes. Use this to plan machining sequence.
| Process | Typical IT Grade | Typical Ra (μm) |
|---|
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