AS568 O-Ring Size Chart

Use the AS568 O-ring size chart to identify standard vulcanized O-ring sizes by dash number, inside diameter (ID), outside diameter (OD), and cross-section (CS).

AS568 sizes provide a consistent dimensional reference for engineers, OEMs, maintenance teams, and buyers specifying O-rings for sealing applications.

Elastostar Rubber Corporation manufactures standard and custom O-rings in Silicone, Viton®/FKM, EPDM, Nitrile (NBR), Neoprene, FVMQ, Butyl, and FFKM for a wide range of industrial applications.

Series	CS Inches	Tolerance	CS Frac.	CS MM	ID Range
Zero	0.070	± .003	1/16	1.78	0.029" - 5.239"
100	0.103	± .003	3/32	2.62	0.049" - 9.737"
200	0.139	± .004	1/8	3.53	0.171" - 17.955"
300	0.210	± .005	3/16	5.33	0.412" - 25.940"
400	0.275	± .006	1/4	6.99	1.350" - 25.940"
900	varies	varies	varies	1.42 - 3.00	0.185" - 2.337"

How to Read the AS568 O-Ring Size Chart

Each AS568 dash number identifies a standardized O-ring size based on defined dimensional requirements.

When using the chart, compare these key dimensions:

Dash Number: Standard designation used to identify the O-ring size.
ID (Inside Diameter): Diameter measured across the inside of the O-ring.
OD (Outside Diameter): Overall diameter measured across the outside of the O-ring.
CS (Cross-Section): Thickness of the O-ring’s circular section.

Use the chart below to compare AS568 O-ring sizes and dimensions in inches and millimeters.

AS568 O-Ring Size Reference Chart

Dash #	CS nominal (in)	ID nominal (in)	OD nominal (in)	CS actual (in)	ID actual (in)	ID tol. ± (in)	CS actual (mm)	ID actual (mm)	ID tol. ± (mm)
001	1/32	1/32	3/32	0.040	0.029	0.004	1.02	0.74	0.10
002	3/64	3/64	9/64	0.050	0.042	0.004	1.27	1.07	0.10
003	1/16	1/16	3/16	0.060	0.056	0.004	1.52	1.42	0.10
004	1/16	5/64	13/64	0.070	0.070	0.005	1.78	1.78	0.13
005	1/16	3/32	7/32	0.070	0.101	0.005	1.78	2.57	0.13
006	1/16	1/8	1/4	0.070	0.114	0.005	1.78	2.90	0.13
007	1/16	5/32	9/32	0.070	0.145	0.005	1.78	3.68	0.13
008	1/16	3/16	5/16	0.070	0.176	0.005	1.78	4.47	0.13
009	1/16	7/32	11/32	0.070	0.208	0.005	1.78	5.28	0.13
010	1/16	1/4	3/8	0.070	0.239	0.005	1.78	6.07	0.13
011	1/16	5/16	7/16	0.070	0.301	0.005	1.78	7.65	0.13
012	1/16	3/8	1/2	0.070	0.364	0.005	1.78	9.25	0.13
013	1/16	7/16	9/16	0.070	0.426	0.005	1.78	10.82	0.13
014	1/16	1/2	5/8	0.070	0.489	0.005	1.78	12.42	0.13
015	1/16	9/16	11/16	0.070	0.551	0.007	1.78	14.00	0.18
016	1/16	5/8	3/4	0.070	0.614	0.009	1.78	15.60	0.23
017	1/16	11/16	13/16	0.070	0.676	0.009	1.78	17.17	0.23
018	1/16	3/4	7/8	0.070	0.739	0.009	1.78	18.77	0.23
019	1/16	13/16	15/16	0.070	0.801	0.009	1.78	20.35	0.23
020	1/16	7/8	1	0.070	0.864	0.009	1.78	21.95	0.23
021	1/16	15/16	1-1/16	0.070	0.926	0.009	1.78	23.52	0.23
022	1/16	1	1-1/8	0.070	0.989	0.010	1.78	25.12	0.25
023	1/16	1-1/16	1-3/16	0.070	1.051	0.010	1.78	26.70	0.25
024	1/16	1-1/8	1-1/4	0.070	1.114	0.010	1.78	28.30	0.25
025	1/16	1-3/16	1-5/16	0.070	1.176	0.011	1.78	29.87	0.28
026	1/16	1-1/4	1-3/8	0.070	1.239	0.011	1.78	31.47	0.28
027	1/16	1-5/16	1-7/16	0.070	1.301	0.011	1.78	33.05	0.28
028	1/16	1-3/8	1-1/2	0.070	1.364	0.013	1.78	34.65	0.33
029	1/16	1-1/2	1-5/8	0.070	1.489	0.013	1.78	37.82	0.33
030	1/16	1-5/8	1-3/4	0.070	1.614	0.013	1.78	41.00	0.33
031	1/16	1-3/4	1-7/8	0.070	1.739	0.015	1.78	44.17	0.38
032	1/16	1-7/8	2	0.070	1.864	0.015	1.78	47.35	0.38
033	1/16	2	2-1/8	0.070	1.989	0.018	1.78	50.52	0.46
034	1/16	2-1/8	2-1/4	0.070	2.114	0.018	1.78	53.70	0.46
035	1/16	2-1/4	2-3/8	0.070	2.239	0.018	1.78	56.87	0.46
036	1/16	2-3/8	2-1/2	0.070	2.364	0.018	1.78	60.05	0.46
037	1/16	2-1/2	2-5/8	0.070	2.489	0.018	1.78	63.22	0.46
038	1/16	2-5/8	2-3/4	0.070	2.614	0.020	1.78	66.40	0.51
039	1/16	2-3/4	2-7/8	0.070	2.739	0.020	1.78	69.57	0.51
040	1/16	2-7/8	3	0.070	2.864	0.020	1.78	72.75	0.51
041	1/16	3	3-1/8	0.070	2.989	0.024	1.78	75.92	0.61
042	1/16	3-1/4	3-3/8	0.070	3.239	0.024	1.78	82.27	0.61
043	1/16	3-1/2	3-5/8	0.070	3.489	0.024	1.78	88.62	0.61
044	1/16	3-3/4	3-7/8	0.070	3.739	0.027	1.78	94.97	0.69
045	1/16	4	4-1/8	0.070	3.989	0.027	1.78	101.32	0.69
046	1/16	4-1/4	4-3/8	0.070	4.239	0.030	1.78	107.67	0.76
047	1/16	4-1/2	4-5/8	0.070	4.489	0.030	1.78	114.02	0.76
048	1/16	4-3/4	4-7/8	0.070	4.739	0.030	1.78	120.37	0.76
049	1/16	5	5-1/8	0.070	4.989	0.037	1.78	126.72	0.94
050	1/16	5-1/4	5-3/8	0.070	5.239	0.037	1.78	133.07	0.94
102	3/32	1/16	1/4	0.103	0.049	0.005	2.62	1.24	0.13
103	3/32	3/32	9/32	0.103	0.081	0.005	2.62	2.06	0.13
104	3/32	1/8	5/16	0.103	0.112	0.005	2.62	2.84	0.13
105	3/32	5/32	11/32	0.103	0.143	0.005	2.62	3.63	0.13
106	3/32	3/16	3/8	0.103	0.174	0.005	2.62	4.42	0.13
107	3/32	7/32	13/32	0.103	0.206	0.005	2.62	5.23	0.13
108	3/32	1/4	7/16	0.103	0.237	0.005	2.62	6.02	0.13
109	3/32	5/16	1/2	0.103	0.299	0.005	2.62	7.59	0.13
110	3/32	3/8	9/16	0.103	0.362	0.005	2.62	9.19	0.13
111	3/32	7/16	5/8	0.103	0.424	0.005	2.62	10.77	0.13
112	3/32	1/2	11/16	0.103	0.487	0.005	2.62	12.37	0.13
113	3/32	9/16	3/4	0.103	0.549	0.007	2.62	13.94	0.18
114	3/32	5/8	13/16	0.103	0.612	0.009	2.62	15.54	0.23
115	3/32	11/16	7/8	0.103	0.674	0.009	2.62	17.12	0.23
116	3/32	3/4	15/16	0.103	0.737	0.009	2.62	18.72	0.23
117	3/32	13/16	1	0.103	0.799	0.010	2.62	20.29	0.25
118	3/32	7/8	1-1/16	0.103	0.862	0.010	2.62	21.89	0.25
119	3/32	15/16	1-1/8	0.103	0.924	0.010	2.62	23.47	0.25
120	3/32	1	1-3/16	0.103	0.987	0.010	2.62	25.07	0.25
121	3/32	1-1/16	1-1/4	0.103	1.049	0.010	2.62	26.64	0.25
122	3/32	1-1/8	1-5/16	0.103	1.112	0.010	2.62	28.24	0.25
123	3/32	1-3/16	1-3/8	0.103	1.174	0.012	2.62	29.82	0.30
124	3/32	1-1/4	1-7/16	0.103	1.237	0.012	2.62	31.42	0.30
125	3/32	1-5/16	1-1/2	0.103	1.299	0.012	2.62	32.99	0.30
126	3/32	1-3/8	1-9/16	0.103	1.362	0.012	2.62	34.59	0.30
127	3/32	1-7/16	1-5/8	0.103	1.424	0.012	2.62	36.17	0.30
128	3/32	1-1/2	1-11/16	0.103	1.487	0.012	2.62	37.77	0.30
129	3/32	1-9/16	1-3/4	0.103	1.549	0.015	2.62	39.34	0.38
130	3/32	1-5/8	1-13/16	0.103	1.612	0.015	2.62	40.94	0.38
131	3/32	1-11/16	1-7/8	0.103	1.674	0.015	2.62	42.52	0.38
132	3/32	1-3/4	1-15/16	0.103	1.737	0.015	2.62	44.12	0.38
133	3/32	1-13/16	2	0.103	1.799	0.015	2.62	45.69	0.38
134	3/32	1-7/8	2-1/16	0.103	1.862	0.015	2.62	47.29	0.38
135	3/32	1-15/16	2-1/8	0.103	1.925	0.017	2.62	48.90	0.43
136	3/32	2	2-3/16	0.103	1.987	0.017	2.62	50.47	0.43
137	3/32	2-1/16	2-1/4	0.103	2.050	0.017	2.62	52.07	0.43
138	3/32	2-1/8	2-5/16	0.103	2.112	0.017	2.62	53.64	0.43
139	3/32	2-3/16	2-3/8	0.103	2.175	0.017	2.62	55.25	0.43
140	3/32	2-1/4	2-7/16	0.103	2.237	0.017	2.62	56.82	0.43
141	3/32	2-5/16	2-1/2	0.103	2.300	0.020	2.62	58.42	0.51
142	3/32	2-3/8	2-9/16	0.103	2.362	0.020	2.62	59.99	0.51
143	3/32	2-7/16	2-5/8	0.103	2.425	0.020	2.62	61.60	0.51
144	3/32	2-1/2	2-11/16	0.103	2.487	0.020	2.62	63.17	0.51
145	3/32	2-9/16	2-3/4	0.103	2.550	0.020	2.62	64.77	0.51
146	3/32	2-5/8	2-13/16	0.103	2.612	0.020	2.62	66.34	0.51
147	3/32	2-11/16	2-7/8	0.103	2.675	0.022	2.62	67.95	0.56
148	3/32	2-3/4	2-15/16	0.103	2.737	0.022	2.62	69.52	0.56
149	3/32	2-13/16	3	0.103	2.800	0.022	2.62	71.12	0.56
150	3/32	2-7/8	3-1/16	0.103	2.862	0.022	2.62	72.69	0.56
151	3/32	3	3-3/16	0.103	2.987	0.024	2.62	75.87	0.61
152	3/32	3-1/4	3-7/16	0.103	3.237	0.024	2.62	82.22	0.61
153	3/32	3-1/2	3-11/16	0.103	3.487	0.024	2.62	88.57	0.61
154	3/32	3-3/4	3-15/16	0.103	3.737	0.028	2.62	94.92	0.71
155	3/32	4	4-3/16	0.103	3.987	0.028	2.62	101.27	0.71
156	3/32	4-1/4	4-7/16	0.103	4.237	0.030	2.62	107.62	0.76
157	3/32	4-1/2	4-11/16	0.103	4.487	0.030	2.62	113.97	0.76
158	3/32	4-3/4	4-15/16	0.103	4.737	0.030	2.62	120.32	0.76
159	3/32	5	5-3/16	0.103	4.987	0.035	2.62	126.67	0.89
160	3/32	5-1/4	5-7/16	0.103	5.237	0.035	2.62	133.02	0.89
161	3/32	5-1/2	5-11/16	0.103	5.487	0.035	2.62	139.37	0.89
162	3/32	5-3/4	5-15/16	0.103	5.737	0.035	2.62	145.72	0.89
163	3/32	6	6-3/16	0.103	5.987	0.035	2.62	152.07	0.89
164	3/32	6-1/4	6-7/16	0.103	6.237	0.040	2.62	158.42	1.02
165	3/32	6-1/2	6-11/16	0.103	6.487	0.040	2.62	164.77	1.02
166	3/32	6-3/4	6-15/16	0.103	6.737	0.040	2.62	171.12	1.02
167	3/32	7	7-3/16	0.103	6.987	0.040	2.62	177.47	1.02
168	3/32	7-1/4	7-7/16	0.103	7.237	0.045	2.62	183.82	1.14
169	3/32	7-1/2	7-11/16	0.103	7.487	0.045	2.62	190.17	1.14
170	3/32	7-3/4	7-15/16	0.103	7.737	0.045	2.62	196.52	1.14
171	3/32	8	8-3/16	0.103	7.987	0.045	2.62	202.87	1.14
172	3/32	8-1/4	8-7/16	0.103	8.237	0.050	2.62	209.22	1.27
173	3/32	8-1/2	8-11/16	0.103	8.487	0.050	2.62	215.57	1.27
174	3/32	8-3/4	8-15/16	0.103	8.737	0.050	2.62	221.92	1.27
175	3/32	9	9-3/16	0.103	8.987	0.050	2.62	228.27	1.27
176	3/32	9-1/4	9-7/16	0.103	9.237	0.055	2.62	234.62	1.40
177	3/32	9-1/2	9-11/16	0.103	9.487	0.055	2.62	240.97	1.40
178	3/32	9-3/4	9-15/16	0.103	9.737	0.055	2.62	247.32	1.40
201	1/8	3/16	7/16	0.139	0.171	0.005	3.53	4.34	0.13
202	1/8	1/4	1/2	0.139	0.234	0.005	3.53	5.94	0.13
203	1/8	5/16	9/16	0.139	0.296	0.005	3.53	7.52	0.13
204	1/8	3/8	5/8	0.139	0.359	0.005	3.53	9.12	0.13
205	1/8	7/16	11/16	0.139	0.421	0.005	3.53	10.69	0.13
206	1/8	1/2	3/4	0.139	0.484	0.005	3.53	12.29	0.13
207	1/8	9/16	13/16	0.139	0.546	0.007	3.53	13.87	0.18
208	1/8	5/8	7/8	0.139	0.609	0.009	3.53	15.47	0.23
209	1/8	11/16	15/16	0.139	0.671	0.009	3.53	17.04	0.23
210	1/8	3/4	1	0.139	0.734	0.010	3.53	18.64	0.25
211	1/8	13/16	1-1/16	0.139	0.796	0.010	3.53	20.22	0.25
212	1/8	7/8	1-1/8	0.139	0.859	0.010	3.53	21.82	0.25
213	1/8	15/16	1-3/16	0.139	0.921	0.010	3.53	23.39	0.25
214	1/8	1	1-1/4	0.139	0.984	0.010	3.53	24.99	0.25
215	1/8	1-1/16	1-5/16	0.139	1.046	0.010	3.53	26.57	0.25
216	1/8	1-1/8	1-3/8	0.139	1.109	0.012	3.53	28.17	0.30
217	1/8	1-3/16	1-7/16	0.139	1.171	0.012	3.53	29.74	0.30
218	1/8	1-1/4	1-1/2	0.139	1.234	0.012	3.53	31.34	0.30
219	1/8	1-5/16	1-9/16	0.139	1.296	0.012	3.53	32.92	0.30
220	1/8	1-3/8	1-5/8	0.139	1.359	0.012	3.53	34.52	0.30
221	1/8	1-7/16	1-11/16	0.139	1.421	0.012	3.53	36.09	0.30
222	1/8	1-1/2	1-3/4	0.139	1.484	0.015	3.53	37.69	0.38
223	1/8	1-5/8	1-7/8	0.139	1.609	0.015	3.53	40.87	0.38
224	1/8	1-3/4	2	0.139	1.734	0.015	3.53	44.04	0.38
225	1/8	1-7/8	2-1/8	0.139	1.859	0.018	3.53	47.22	0.46
226	1/8	2	2-1/4	0.139	1.984	0.018	3.53	50.39	0.46
227	1/8	2-1/8	2-3/8	0.139	2.109	0.018	3.53	53.57	0.46
228	1/8	2-1/4	2-1/2	0.139	2.234	0.020	3.53	56.74	0.51
229	1/8	2-3/8	2-5/8	0.139	2.359	0.020	3.53	59.92	0.51
230	1/8	2-1/2	2-3/4	0.139	2.484	0.020	3.53	63.09	0.51
231	1/8	2-5/8	2-7/8	0.139	2.609	0.020	3.53	66.27	0.51
232	1/8	2-3/4	3	0.139	2.734	0.024	3.53	69.44	0.61
233	1/8	2-7/8	3-1/8	0.139	2.859	0.024	3.53	72.62	0.61
234	1/8	3	3-1/4	0.139	2.984	0.024	3.53	75.79	0.61
235	1/8	3-1/8	3-3/8	0.139	3.109	0.024	3.53	78.97	0.61
236	1/8	3-1/4	3-1/2	0.139	3.234	0.024	3.53	82.14	0.61
237	1/8	3-3/8	3-5/8	0.139	3.359	0.024	3.53	85.32	0.61
238	1/8	3-1/2	3-3/4	0.139	3.484	0.024	3.53	88.49	0.61
239	1/8	3-5/8	3-7/8	0.139	3.609	0.028	3.53	91.67	0.71
240	1/8	3-3/4	4	0.139	3.734	0.028	3.53	94.84	0.71
241	1/8	3-7/8	4-1/8	0.139	3.859	0.028	3.53	98.02	0.71
242	1/8	4	4-1/4	0.139	3.984	0.028	3.53	101.19	0.71
243	1/8	4-1/8	4-3/8	0.139	4.109	0.028	3.53	104.37	0.71
244	1/8	4-1/4	4-1/2	0.139	4.234	0.030	3.53	107.54	0.76
245	1/8	4-3/8	4-5/8	0.139	4.359	0.030	3.53	110.72	0.76
246	1/8	4-1/2	4-3/4	0.139	4.484	0.030	3.53	113.89	0.76
247	1/8	4-5/8	4-7/8	0.139	4.609	0.030	3.53	117.07	0.76
248	1/8	4-3/4	5	0.139	4.734	0.030	3.53	120.24	0.76
249	1/8	4-7/8	5-1/8	0.139	4.859	0.035	3.53	123.42	0.89
250	1/8	5	5-1/4	0.139	4.984	0.035	3.53	126.59	0.89
251	1/8	5-1/8	5-3/8	0.139	5.109	0.035	3.53	129.77	0.89
252	1/8	5-1/4	5-1/2	0.139	5.234	0.035	3.53	132.94	0.89
253	1/8	5-3/8	5-5/8	0.139	5.359	0.035	3.53	136.12	0.89
254	1/8	5-1/2	5-3/4	0.139	5.484	0.035	3.53	139.29	0.89
255	1/8	5-5/8	5-7/8	0.139	5.609	0.035	3.53	142.47	0.89
256	1/8	5-3/4	6	0.139	5.734	0.035	3.53	145.64	0.89
257	1/8	5-7/8	6-1/8	0.139	5.859	0.035	3.53	148.82	0.89
258	1/8	6	6-1/4	0.139	5.984	0.035	3.53	151.99	0.89
259	1/8	6-1/4	6-1/2	0.139	6.234	0.040	3.53	158.34	1.02
260	1/8	6-1/2	6-3/4	0.139	6.484	0.040	3.53	164.69	1.02
261	1/8	6-3/4	7	0.139	6.734	0.040	3.53	171.04	1.02
262	1/8	7	7-1/4	0.139	6.984	0.040	3.53	177.39	1.02
263	1/8	7-1/4	7-1/2	0.139	7.234	0.045	3.53	183.74	1.14
264	1/8	7-1/2	7-3/4	0.139	7.484	0.045	3.53	190.09	1.14
265	1/8	7-3/4	8	0.139	7.734	0.045	3.53	196.44	1.14
266	1/8	8	8-1/4	0.139	7.984	0.045	3.53	202.79	1.14
267	1/8	8-1/4	8-1/2	0.139	8.234	0.050	3.53	209.14	1.27
268	1/8	8-1/2	8-3/4	0.139	8.484	0.050	3.53	215.49	1.27
269	1/8	8-3/4	9	0.139	8.734	0.050	3.53	221.84	1.27
270	1/8	9	9-1/4	0.139	8.984	0.050	3.53	228.19	1.27
271	1/8	9-1/4	9-1/2	0.139	9.234	0.055	3.53	234.54	1.40
272	1/8	9-1/2	9-3/4	0.139	9.484	0.055	3.53	240.89	1.40
273	1/8	9-3/4	10	0.139	9.734	0.055	3.53	247.24	1.40
274	1/8	10	10-1/4	0.139	9.984	0.055	3.53	253.59	1.40
275	1/8	10-1/2	10-3/4	0.139	10.484	0.055	3.53	266.29	1.40
276	1/8	11	11-1/4	0.139	10.984	0.065	3.53	278.99	1.65
277	1/8	11-1/2	11-3/4	0.139	11.484	0.065	3.53	291.69	1.65
278	1/8	12	12-1/4	0.139	11.984	0.065	3.53	304.39	1.65
279	1/8	13	13-1/4	0.139	12.984	0.065	3.53	329.79	1.65
280	1/8	14	14-1/4	0.139	13.984	0.065	3.53	355.19	1.65
281	1/8	15	15-1/4	0.139	14.984	0.065	3.53	380.59	1.65
282	1/8	16	16-1/4	0.139	15.955	0.075	3.53	405.26	1.91
283	1/8	17	17-1/4	0.139	16.955	0.080	3.53	430.66	2.03
284	1/8	18	18-1/4	0.139	17.955	0.085	3.53	456.06	2.16
309	3/16	7/16	13/16	0.210	0.412	0.005	5.33	10.46	0.13
310	3/16	1/2	7/8	0.210	0.475	0.005	5.33	12.07	0.13
311	3/16	9/16	15/16	0.210	0.537	0.007	5.33	13.64	0.18
312	3/16	5/8	1	0.210	0.600	0.009	5.33	15.24	0.23
313	3/16	11/16	1-1/16	0.210	0.662	0.009	5.33	16.81	0.23
314	3/16	3/4	1-1/8	0.210	0.725	0.010	5.33	18.42	0.25
315	3/16	13/16	1-3/16	0.210	0.787	0.010	5.33	19.99	0.25
316	3/16	7/8	1-1/4	0.210	0.850	0.010	5.33	21.59	0.25
317	3/16	15/16	1-5/16	0.210	0.912	0.010	5.33	23.16	0.25
318	3/16	1	1-3/8	0.210	0.975	0.010	5.33	24.77	0.25
319	3/16	1-1/16	1-7/16	0.210	1.037	0.010	5.33	26.34	0.25
320	3/16	1-1/8	1-1/2	0.210	1.100	0.012	5.33	27.94	0.30
321	3/16	1-3/16	1-9/16	0.210	1.162	0.012	5.33	29.51	0.30
322	3/16	1-1/4	1-5/8	0.210	1.225	0.012	5.33	31.12	0.30
323	3/16	1-5/16	1-11/16	0.210	1.287	0.012	5.33	32.69	0.30
324	3/16	1-3/8	1-3/4	0.210	1.350	0.012	5.33	34.29	0.30
325	3/16	1-1/2	1-7/8	0.210	1.475	0.015	5.33	37.47	0.38
326	3/16	1-5/8	2	0.210	1.600	0.015	5.33	40.64	0.38
327	3/16	1-3/4	2-1/8	0.210	1.725	0.015	5.33	43.82	0.38
328	3/16	1-7/8	2-1/4	0.210	1.850	0.015	5.33	46.99	0.38
329	3/16	2	2-3/8	0.210	1.975	0.018	5.33	50.17	0.46
330	3/16	2-1/8	2-1/2	0.210	2.100	0.018	5.33	53.34	0.46
331	3/16	2-1/4	2-5/8	0.210	2.225	0.018	5.33	56.52	0.46
332	3/16	2-3/8	2-3/4	0.210	2.350	0.018	5.33	59.69	0.46
333	3/16	2-1/2	2-7/8	0.210	2.475	0.020	5.33	62.87	0.51
334	3/16	2-5/8	3	0.210	2.600	0.020	5.33	66.04	0.51
335	3/16	2-3/4	3-1/8	0.210	2.725	0.020	5.33	69.22	0.51
336	3/16	2-7/8	3-1/4	0.210	2.850	0.020	5.33	72.39	0.51
337	3/16	3	3-3/8	0.210	2.975	0.024	5.33	75.57	0.61
338	3/16	3-1/8	3-1/2	0.210	3.100	0.024	5.33	78.74	0.61
339	3/16	3-1/4	3-5/8	0.210	3.225	0.024	5.33	81.92	0.61
340	3/16	3-3/8	3-3/4	0.210	3.350	0.024	5.33	85.09	0.61
341	3/16	3-1/2	3-7/8	0.210	3.475	0.024	5.33	88.27	0.61
342	3/16	3-5/8	4	0.210	3.600	0.028	5.33	91.44	0.71
343	3/16	3-3/4	4-1/8	0.210	3.725	0.028	5.33	94.62	0.71
344	3/16	3-7/8	4-1/4	0.210	3.850	0.028	5.33	97.79	0.71
345	3/16	4	4-3/8	0.210	3.975	0.028	5.33	100.97	0.71
346	3/16	4-1/8	4-1/2	0.210	4.100	0.028	5.33	104.14	0.71
347	3/16	4-1/4	4-5/8	0.210	4.225	0.030	5.33	107.32	0.76
348	3/16	4-3/8	4-3/4	0.210	4.350	0.030	5.33	110.49	0.76
349	3/16	4-1/2	4-7/8	0.210	4.475	0.030	5.33	113.67	0.76
350	3/16	4-5/8	5	0.210	4.600	0.030	5.33	116.84	0.76
351	3/16	4-3/4	5-1/8	0.210	4.725	0.030	5.33	120.02	0.76
352	3/16	4-7/8	5-1/4	0.210	4.850	0.030	5.33	123.19	0.76
353	3/16	5	5-3/8	0.210	4.975	0.037	5.33	126.37	0.94
354	3/16	5-1/8	5-1/2	0.210	5.100	0.037	5.33	129.54	0.94
355	3/16	5-1/4	5-5/8	0.210	5.225	0.037	5.33	132.72	0.94
356	3/16	5-3/8	5-3/4	0.210	5.350	0.037	5.33	135.89	0.94
357	3/16	5-1/2	5-7/8	0.210	5.475	0.037	5.33	139.07	0.94
358	3/16	5-5/8	6	0.210	5.600	0.037	5.33	142.24	0.94
359	3/16	5-3/4	6-1/8	0.210	5.725	0.037	5.33	145.42	0.94
360	3/16	5-7/8	6-1/4	0.210	5.850	0.037	5.33	148.59	0.94
361	3/16	6	6-3/8	0.210	5.975	0.037	5.33	151.77	0.94
362	3/16	6-1/4	6-5/8	0.210	6.225	0.040	5.33	158.12	1.02
363	3/16	6-1/2	6-7/8	0.210	6.475	0.040	5.33	164.47	1.02
364	3/16	6-3/4	7-1/8	0.210	6.725	0.040	5.33	170.82	1.02
365	3/16	7	7-3/8	0.210	6.975	0.040	5.33	177.17	1.02
366	3/16	7-1/4	7-5/8	0.210	7.225	0.045	5.33	183.52	1.14
367	3/16	7-1/2	7-7/8	0.210	7.475	0.045	5.33	189.87	1.14
368	3/16	7-3/4	8-1/8	0.210	7.725	0.045	5.33	196.22	1.14
369	3/16	8	8-3/8	0.210	7.975	0.045	5.33	202.57	1.14
370	3/16	8-1/4	8-5/8	0.210	8.225	0.050	5.33	208.92	1.27
371	3/16	8-1/2	8-7/8	0.210	8.475	0.050	5.33	215.27	1.27
372	3/16	8-3/4	9-1/8	0.210	8.725	0.050	5.33	221.62	1.27
373	3/16	9	9-3/8	0.210	8.975	0.050	5.33	227.97	1.27
374	3/16	9-1/4	9-5/8	0.210	9.225	0.055	5.33	234.32	1.40
375	3/16	9-1/2	9-7/8	0.210	9.475	0.055	5.33	240.67	1.40
376	3/16	9-3/4	10-1/8	0.210	9.725	0.055	5.33	247.02	1.40
377	3/16	10	10-3/8	0.210	9.975	0.055	5.33	253.37	1.40
378	3/16	10-1/2	10-7/8	0.210	10.475	0.060	5.33	266.07	1.52
379	3/16	11	11-3/8	0.210	10.975	0.060	5.33	278.77	1.52
380	3/16	11-1/2	11-7/8	0.210	11.475	0.065	5.33	291.47	1.65
381	3/16	12	12-3/8	0.210	11.975	0.065	5.33	304.17	1.65
382	3/16	13	13-3/8	0.210	12.975	0.065	5.33	329.57	1.65
383	3/16	14	14-3/8	0.210	13.975	0.070	5.33	354.97	1.78
384	3/16	15	15-3/8	0.210	14.975	0.070	5.33	380.37	1.78
385	3/16	16	16-3/8	0.210	15.955	0.075	5.33	405.26	1.91
386	3/16	17	17-3/8	0.210	16.955	0.080	5.33	430.66	2.03
387	3/16	18	18-3/8	0.210	17.955	0.085	5.33	456.06	2.16
388	3/16	19	19-3/8	0.210	18.955	0.090	5.33	481.46	2.29
389	3/16	20	20-3/8	0.210	19.955	0.095	5.33	506.86	2.41
390	3/16	21	21-3/8	0.210	20.955	0.095	5.33	532.26	2.41
391	3/16	22	22-3/8	0.210	21.955	0.095	5.33	557.66	2.41
392	3/16	23	23-3/8	0.210	22.940	0.105	5.33	582.68	2.67
393	3/16	24	24-3/8	0.210	23.940	0.110	5.33	608.08	2.79
394	3/16	25	25-3/8	0.210	24.940	0.115	5.33	633.48	2.92
395	3/16	26	26-3/8	0.210	25.940	0.120	5.33	658.88	3.05
400	1/4	1-3/8	1-7/8	0.275	1.350	0.012	6.99	34.29	0.30
401	1/4	1-1/2	2	0.275	1.475	0.015	6.99	37.47	0.38
402	1/4	1-5/8	2-1/8	0.275	1.600	0.015	6.99	40.64	0.38
403	1/4	1-3/4	2-1/4	0.275	1.725	0.015	6.99	43.82	0.38
404	1/4	1-7/8	2-3/8	0.275	1.850	0.015	6.99	46.99	0.38
405	1/4	2	2-1/2	0.275	1.975	0.018	6.99	50.17	0.46
406	1/4	2-1/8	2-5/8	0.275	2.100	0.018	6.99	53.34	0.46
407	1/4	2-1/4	2-3/4	0.275	2.225	0.018	6.99	56.52	0.46
408	1/4	2-3/8	2-7/8	0.275	2.350	0.018	6.99	59.69	0.46
409	1/4	2-1/2	3	0.275	2.475	0.020	6.99	62.87	0.51
410	1/4	2-5/8	3-1/8	0.275	2.600	0.020	6.99	66.04	0.51
411	1/4	2-3/4	3-1/4	0.275	2.725	0.020	6.99	69.22	0.51
412	1/4	2-7/8	3-3/8	0.275	2.850	0.020	6.99	72.39	0.51
413	1/4	3	3-1/2	0.275	2.975	0.024	6.99	75.57	0.61
414	1/4	3-1/8	3-5/8	0.275	3.100	0.024	6.99	78.74	0.61
415	1/4	3-1/4	3-3/4	0.275	3.225	0.024	6.99	81.92	0.61
416	1/4	3-3/8	3-7/8	0.275	3.350	0.024	6.99	85.09	0.61
417	1/4	3-1/2	4	0.275	3.475	0.024	6.99	88.27	0.61
418	1/4	3-5/8	4-1/8	0.275	3.600	0.028	6.99	91.44	0.71
419	1/4	3-3/4	4-1/4	0.275	3.725	0.028	6.99	94.62	0.71
420	1/4	3-7/8	4-3/8	0.275	3.850	0.028	6.99	97.79	0.71
421	1/4	4	4-1/2	0.275	3.975	0.028	6.99	100.97	0.71
422	1/4	4-1/8	4-5/8	0.275	4.100	0.028	6.99	104.14	0.71
423	1/4	4-1/4	4-3/4	0.275	4.225	0.030	6.99	107.32	0.76
424	1/4	4-3/8	4-7/8	0.275	4.350	0.030	6.99	110.49	0.76
425	1/4	4-1/2	5	0.275	4.475	0.033	6.99	113.67	0.84
426	1/4	4-5/8	5-1/8	0.275	4.600	0.033	6.99	116.84	0.84
427	1/4	4-3/4	5-1/4	0.275	4.725	0.033	6.99	120.02	0.84
428	1/4	4-7/8	5-3/8	0.275	4.850	0.033	6.99	123.19	0.84
429	1/4	5	5-1/2	0.275	4.975	0.037	6.99	126.37	0.94
430	1/4	5-1/8	5-5/8	0.275	5.100	0.037	6.99	129.54	0.94
431	1/4	5-1/4	5-3/4	0.275	5.225	0.037	6.99	132.72	0.94
432	1/4	5-3/8	5-7/8	0.275	5.350	0.037	6.99	135.89	0.94
433	1/4	5-1/2	6	0.275	5.475	0.037	6.99	139.07	0.94
434	1/4	5-5/8	6-1/8	0.275	5.600	0.037	6.99	142.24	0.94
435	1/4	5-3/4	6-1/4	0.275	5.725	0.037	6.99	145.42	0.94
436	1/4	5-7/8	6-3/8	0.275	5.850	0.037	6.99	148.59	0.94
437	1/4	6	6-1/2	0.275	5.975	0.037	6.99	151.77	0.94
438	1/4	6-1/4	6-3/4	0.275	6.225	0.040	6.99	158.12	1.02
439	1/4	6-1/2	7	0.275	6.475	0.040	6.99	164.47	1.02
440	1/4	6-3/4	7-1/4	0.275	6.725	0.040	6.99	170.82	1.02
441	1/4	7	7-1/2	0.275	6.975	0.040	6.99	177.17	1.02
442	1/4	7-1/4	7-3/4	0.275	7.225	0.045	6.99	183.52	1.14
443	1/4	7-1/2	8	0.275	7.475	0.045	6.99	189.87	1.14
444	1/4	7-3/4	8-1/4	0.275	7.725	0.045	6.99	196.22	1.14
445	1/4	8	8-1/2	0.275	7.975	0.045	6.99	202.57	1.14
446	1/4	8-1/2	9	0.275	8.475	0.055	6.99	215.27	1.40
447	1/4	9	9-1/2	0.275	8.975	0.055	6.99	227.97	1.40
448	1/4	9-1/2	10	0.275	9.475	0.055	6.99	240.67	1.40
449	1/4	10	10-1/2	0.275	9.975	0.055	6.99	253.37	1.40
450	1/4	10-1/2	11	0.275	10.475	0.060	6.99	266.07	1.52
451	1/4	11	11-1/2	0.275	10.975	0.060	6.99	278.77	1.52
452	1/4	11-1/2	12	0.275	11.475	0.060	6.99	291.47	1.52
453	1/4	12	12-1/2	0.275	11.975	0.060	6.99	304.17	1.52
454	1/4	12-1/2	13	0.275	12.475	0.060	6.99	316.87	1.52
455	1/4	13	13-1/2	0.275	12.975	0.060	6.99	329.57	1.52
456	1/4	13-1/2	14	0.275	13.475	0.070	6.99	342.27	1.78
457	1/4	14	14-1/2	0.275	13.975	0.070	6.99	354.97	1.78
458	1/4	14-1/2	15	0.275	14.475	0.070	6.99	367.67	1.78
459	1/4	15	15-1/2	0.275	14.975	0.070	6.99	380.37	1.78
460	1/4	15-1/2	16	0.275	15.475	0.070	6.99	393.07	1.78
461	1/4	16	16-1/2	0.275	15.955	0.075	6.99	405.26	1.91
462	1/4	16-1/2	17	0.275	16.455	0.075	6.99	417.96	1.91
463	1/4	17	17-1/2	0.275	16.955	0.080	6.99	430.66	2.03
464	1/4	17-1/2	18	0.275	17.455	0.085	6.99	443.36	2.16
465	1/4	18	18-1/2	0.275	17.955	0.085	6.99	456.06	2.16
466	1/4	18-1/2	19	0.275	18.455	0.085	6.99	468.76	2.16
467	1/4	19	19-1/2	0.275	18.955	0.090	6.99	481.46	2.29
468	1/4	19-1/2	20	0.275	19.455	0.090	6.99	494.16	2.29
469	1/4	20	20-1/2	0.275	19.955	0.095	6.99	506.86	2.41
470	1/4	21	21-1/2	0.275	20.955	0.095	6.99	532.26	2.41
471	1/4	22	22-1/2	0.275	21.955	0.100	6.99	557.66	2.54
472	1/4	23	23-1/2	0.275	22.940	0.105	6.99	582.68	2.67
473	1/4	24	24-1/2	0.275	23.940	0.110	6.99	608.08	2.79
474	1/4	25	25-1/2	0.275	24.940	0.115	6.99	633.48	2.92
475	1/4	26	26-1/2	0.275	25.940	0.120	6.99	658.88	3.05
901				0.056	0.185	0.005	1.42	4.70	0.13
902				0.064	0.239	0.005	1.63	6.07	0.13
903				0.064	0.301	0.005	1.63	7.65	0.13
904				0.072	0.351	0.005	1.83	8.92	0.13
905				0.072	0.414	0.005	1.83	10.52	0.13
906				0.078	0.468	0.005	1.98	11.89	0.13
907				0.082	0.530	0.007	2.08	13.46	0.18
908				0.087	0.644	0.009	2.21	16.36	0.23
909				0.097	0.706	0.009	2.46	17.93	0.23
910				0.097	0.755	0.009	2.46	19.18	0.23
911				0.116	0.863	0.009	2.95	21.92	0.23
912				0.116	0.924	0.009	2.95	23.47	0.23
913				0.116	0.986	0.010	2.95	25.04	0.25
914				0.116	1.047	0.010	2.95	26.59	0.25
916				0.116	1.171	0.010	2.95	29.74	0.25
918				0.116	1.355	0.012	2.95	34.42	0.30
920				0.118	1.475	0.014	3.00	37.47	0.36
924				0.118	1.720	0.014	3.00	43.69	0.36
928				0.118	2.090	0.018	3.00	53.09	0.46
932				0.118	2.337	0.018	3.00	59.36	0.46

Selecting the Right O-Ring for Your Application

Finding the correct AS568 O-ring size is only one part of seal selection. The material and design must also be suitable for the application’s operating conditions. Consider:

Operating temperature

Material hardness

Pressure

Required service life

Groove dimensions & O-ring compression

Oils, fuels, water, chemicals, or other media

Static or dynamic sealing

Environmental exposure

A dimensionally correct O-ring may still perform poorly if its material, hardness, or operating limits are not appropriate for the application.

AS568 O-Ring Material Options

An AS568 dash number identifies the O-ring size, not the material. Material should be selected separately according to the sealing environment.

We support O-ring requirements in a range of elastomers, including:

Silicone: Commonly selected for temperature flexibility, ozone resistance, and weather resistance.
Viton®/FKM: Often considered for applications involving elevated temperatures, oils, fuels, lubricants, and many chemicals.
EPDM: Commonly used for water, steam, ozone, weather, and outdoor sealing applications.
Nitrile (NBR): Widely used with petroleum-based oils, greases, and general industrial fluids.

Depending on the application, Neoprene, FVMQ (fluorosilicone), Butyl, and FFKM may also be considered. Material selection should be based on the actual temperature, pressure, sealing media, movement, and environmental conditions of the application.

Need an O-Ring Size Outside the AS568 Standard?

Not every sealing requirement matches a standard AS568 dash size. Equipment modifications, legacy components, unusual groove dimensions, prototypes, and large sealing assemblies may require a custom O-ring size.

Elastostar Rubber Corporation manufactures custom and large-diameter O-rings based on customer drawings, CAD files, dimensions, existing samples, material requirements, hardness, quantities, and operating conditions.

Depending on the design and size requirements, manufacturing options can include molded, spliced, and vulcanized O-rings.

AS568 O-Ring Size FAQs

What is an AS568 O-ring size?

An AS568 O-ring size is a standardized dimensional designation identified by a dash number. The dash number corresponds to defined O-ring dimensions used to simplify size identification and specification.

What do ID, OD, and CS mean on an O-ring size chart?

ID means inside diameter, OD means outside diameter, and CS means cross-section. Together, these measurements describe the physical size of an O-ring.

Does an AS568 dash number identify the O-ring material?

No, an AS568 dash number identifies the size, not the elastomer material. Silicone, Viton®/FKM, EPDM, Nitrile, and other materials can be selected separately based on application requirements.

How do I identify an AS568 size if I don't know the dash number?

Measure the O-ring’s inside diameter and cross-section as accurately as possible and compare those dimensions with the AS568 size chart. For used O-rings, consider that wear, stretching, compression, or swelling may affect the measured dimensions.

What if my required O-ring size is not listed in the AS568 chart?

A custom O-ring may be required when the dimensions do not correspond to a standard AS568 dash size. We manufacture non-standard and large-diameter O-rings based on dimensions, drawings, samples, materials, and application requirements.

Can AS568 O-rings be made from different rubber materials?

Yes, depending on application requirements, O-rings can be manufactured from Silicone, Viton®/FKM, EPDM, Nitrile (NBR), Neoprene, FVMQ, Butyl, FFKM, and other suitable elastomers.

Need Help Identifying the Right O-Ring?

If you know the AS568 dash number, provide it when requesting an O-ring. If the dash number is unknown, provide the ID, OD and/or cross-section, along with the material and application conditions when available.

For custom or replacement applications, you can also provide a drawing, CAD file, or existing sample for evaluation.

Contact Elastostar Rubber Corporation to discuss standard, custom, or large-diameter O-ring requirements.