AS568 O-Ring Size Chart

AS568 is the American standard for O-ring sizes. Use this chart to find the right size.

How to Measure an O-Ring

You need two measurements:

1. Inside Diameter (ID) - Measure across the inside opening
2. Cross-Section (CS) - Measure the thickness of the ring

Outside Diameter (OD) = ID + (2 × CS)

Common AS568 Sizes

Small Sizes (0.040" Cross-Section)

AS568	ID (in)	CS (in)
-001	0.029	0.040
-002	0.042	0.040
-003	0.055	0.040

Medium Sizes (0.070" Cross-Section)

AS568	ID (in)	CS (in)
-110	0.239	0.070
-111	0.301	0.070
-112	0.364	0.070

Standard Sizes (0.103" Cross-Section)

AS568	ID (in)	CS (in)
-210	0.364	0.103
-211	0.460	0.103
-212	0.547	0.103

Large Sizes (0.139" Cross-Section)

AS568	ID (in)	CS (in)
-310	0.547	0.139
-311	0.673	0.139
-312	0.736	0.139

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