Seal design workspace

O-Ring Geometry Calculator

Describe the sealing application, then compare every standard AS568 O-ring that fits. Each option includes tolerance-aware fit checks, gland dimensions, material prompts, and a printable representative channel and mating-geometry drawing.

Loading AS568 catalog… Radial piston, radial rod, axial face, and boss applications Inch and metric input/output

Application questionnaire

Tell us what the seal must do

Inputs marked * are required
1. Geometry and motion
2. Known hardware
3. Pressure, clearance, and environment

Disclaimer: Use calculations at your own risk. For critical applications, verify results against your governing standards/specifications.

Parts sourcing

Amazon links are ready for a future Associates tag

Each result creates a size-, material-, and hardness-specific Amazon search link. No Amazon Associates tracking ID is active yet, so the current links are ordinary Amazon search links. After enrollment, one configuration value can add the approved affiliate tag to every generated link.

Future disclosure: As an Amazon Associate, NumberNumber.net may earn from qualifying purchases. Product listings are not engineering endorsements; verify size, compound, hardness, certification, and seller documentation.

How the fit search works

01

Screen the complete table

The calculator checks all built-in AS568 general sizes, plus the boss series when that application is selected. It does not stop after the first plausible match.

02

Build the gland envelope

Cross-section-specific static, dynamic, radial, or axial gland depth and width guidance is applied, including optional backup-ring space.

03

Check fit and fill

Piston candidates are checked by I.D. stretch, rod candidates by O.D. interference, and face seals by mean-diameter change. Squeeze, tolerance envelope, and gland fill are reported.

04

Flag engineering review

Pressure, extrusion gap, motion, temperature, and media prompt material, hardness, and backup-ring review without pretending to replace compound-specific supplier validation.

Engineering references and scope

The AS568 dimensions and tolerances in this calculator are based on Apple Rubber Products’ AS568 Standard O-Rings Quick Reference Chart (03/2022). General gland ranges are based on its published static and dynamic gland-design tables. For deeper design review, consult the Parker O-Ring Handbook .

This first version covers AS568 inch sizes. ISO 3601 metric sizes, vacuum-specific groove rules, dovetail glands, noncircular face grooves, and compound-specific swell calculations are outside the current fit engine.

FAQ

Why can more than one O-ring fit the same application?

Several cross-section families may fit the same diameter when enough radial or axial space is available. Different rings trade groove depth, groove width, tolerance sensitivity, assembly stretch, friction, and extrusion resistance. The calculator keeps every dimensional match visible so the designer can compare them.

What does “tolerance envelope” mean here?

It combines the entered hardware diameter tolerance, the published O-ring I.D. and cross-section tolerances, and the recommended gland-depth range to show how stretch or interference can move at dimensional extremes.

Can I use the drawing directly on a manufacturing print?

Treat it as a concept and review artifact. Before release, add the governing standard, verified material and hardness, surface finish, edge breaks, lead-in, inspection method, complete hardware tolerances, and application-specific validation.

Does the calculator choose the final elastomer compound?

No. It screens a few common material families against broad temperature and media categories. Exact compound compatibility depends on concentration, exposure time, pressure, decompression, cleaning agents, regulatory requirements, and supplier formulation.