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O-Ring Groove Design Calculator

Calculate groove depth, groove width, and gland fill percentage for O-ring seal design based on cross-section diameter and desired compression.

O-ring inner diameter in mm.
O-ring cross-section (cord) diameter in mm. E.g. AS568 -214 = 3.53 mm; -210 = 2.62 mm.
Desired O-ring compression %. Static face seal: 15–25%. Static radial: 15–25%. Dynamic: 10–20%.

Results

Groove Depth2.824 mm
Groove Width5.295 mm
Gland Fill65.4% (target: 60–85%)

📖What is it?

O-ring groove (gland) design determines how much the O-ring is compressed and how much space remains in the gland for O-ring volume expansion from pressure, temperature, and fluid swell. Too much compression causes premature wear; too little causes leakage. Gland fill (% of groove volume occupied by the O-ring) must stay in the 60–85% range to allow for thermal/pressure expansion.

🎯How to use

Enter the O-ring inner diameter, cross-section diameter (from the part number or datasheet), and your desired compression percentage. The calculator outputs groove depth (controls compression), groove width (typically 1.5× CS), and the gland fill percentage.

💡Example scenario

AS568 -214 O-ring (CS = 3.53 mm, ID = 50 mm) at 20% compression. Groove depth = 3.53 × (1 − 0.20) = 2.824 mm. Groove width = 3.53 × 1.5 = 5.295 mm. Gland fill = (π × 3.53² / 4) / (5.295 × 2.824) × 100 ≈ 65.4% — within the acceptable 60–85% range.

🏆Pro tip

For dynamic applications (pistons, rods), use lower compression (10–15%) to reduce friction and heat. Static face seals can use up to 25% compression. Lubricate O-rings during assembly with a compatible grease to prevent installation damage. Surface finish in the groove should be Ra 0.8–1.6 μm for dynamic applications.