What does an AS568 O-ring dash number mean?

An AS568 dash number identifies a standard O-ring size with specified nominal inside diameter and cross-section dimensions.

How do I find an O-ring size?

Search by AS568 dash number or by a known inside diameter, outside diameter or cross section dimension.

What is the actual size of an O-ring?

The actual nominal size is described by its inside diameter, cross section and resulting outside diameter.

FREE SHOP TOOL

O-Ring Size Chart & AS568 Size Finder

Start typing a dash number or dimension to instantly find matching O-ring sizes. View actual O-ring dimensions including inside diameter (ID), outside diameter (OD), and cross section (CS) in inches or millimeters.

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Examples:

O-RING SIZE REFERENCE

How to Find an AS568 O-Ring Size

AS568 O-rings are identified by a dash number. Each size specifies an inside diameter and cross-section. If you know one of those dimensions, enter it in the finder above to narrow the results.

ID Inside diameter of the O-ring.

CS Cross-section, or thickness of the O-ring cord.

OD Outside diameter, calculated as ID + 2 × CS.

Common AS568 Cross-Section Series

0xx0.070 in / 1.78 mm

1xx0.103 in / 2.62 mm

2xx0.139 in / 3.53 mm

3xx0.210 in / 5.33 mm

4xx0.275 in / 6.99 mm

Dimensions are reference values for identifying standard O-ring sizes. Verify current engineering standards and application requirements for critical sealing designs.