ISO 3601 is a multi-part standard for O-rings and their groove dimensions. Part 1 covers O-ring sizes, Part 2 covers housing dimensions (grooves) for general applications, Part 3 covers quality acceptance criteria, and Part 4 covers anti-extrusion rings (backup rings).

How much compression should an O-ring have?

Typical O-ring compression (squeeze) is 10–30% of the cross-section diameter. For static seals: 15–25%. For dynamic seals: 10–20%. Too much compression increases friction; too little causes leakage.

What surface finish is required for O-ring grooves?

For static seals: Ra ≤ 3.2 μm on groove surfaces. For dynamic seals: Ra ≤ 0.4 μm on the sliding surface, Ra ≤ 1.6 μm on groove bottom and sides. No sharp edges; break all corners with R0.2–0.5 mm.

How do I calculate groove depth for an O-ring?

Groove depth = O-ring cross-section × (1 - squeeze ratio). For example, with a 3.53mm cross-section and 20% squeeze: groove depth = 3.53 × 0.80 = 2.82mm. Add tolerance per ISO 3601-2.

What is the groove fill ratio?

Groove fill ratio is the percentage of groove volume occupied by the O-ring. Recommended: 70–85% for static, 75–85% for dynamic. Below 60% risks spiral failure in dynamic applications. Above 90% risks hydraulic lock.

Free Engineering Tool

Seal Groove Tolerances — ISO 3601

Look up O-ring groove dimensions and tolerances per ISO 3601. Select seal type and cross-section size to see groove depth, width, and surface finish requirements.

ISO 3601-2O-Ring GroovesStatic & Dynamic

Groove Dimensions

Groove Depth

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Groove Width

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Squeeze (%)

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Surface Finish

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Edge Break Radius

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Groove Depth Calculation

Typical squeeze: 15–25% for static, 10–20% for dynamic seals.

Standard Groove Dimensions (ISO 3601-2)

d2 (mm)	Groove Depth Static	Groove Width Static	Groove Depth Dynamic	Groove Width Dynamic
1.78	1.35	2.5	1.47	2.4
2.62	2.05	3.6	2.20	3.4
3.53	2.82	4.7	2.95	4.6
5.33	4.34	7.0	4.50	6.9
6.99	5.74	9.1	5.90	9.0

All dimensions in mm. Tolerances: groove depth ±0.05 to ±0.10 mm, groove width ±0.10 to ±0.15 mm depending on size.

Seal Groove Tolerances — ISO 3601 | Free Online Tool

Published by Nikolai Shelkovenko on February 15, 2026 February 15, 2026

Groove Dimensions

Groove Depth Calculation

Standard Groove Dimensions (ISO 3601-2)