AS568 O-Ring Size Chart

The complete AS568 dash-number series (-001 through -475) with inside diameters, cross-sections and tolerances — the US aerospace O-ring standard published by SAE. ARC molds every AS568 size to your compound, hardness and color.

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Sourcing AS568 O-rings for your build

If your drawing calls out an AS568 dash number, this chart gives you the exact inside diameter, cross-section and tolerance for every size in the series — so you can confirm the O-ring a groove needs before you request a quote. AS568 is the most widely specified O-ring standard on North American industrial and aerospace equipment, and getting the size and tolerance right is the difference between a seal that holds and an unplanned line-down.

American Rubber Corp molds every AS568 size to your compound, hardness and color — not off a shelf. Whether you need a drop-in replacement in a better material (Viton/FKM, EPDM, silicone, nitrile, FFKM) or a high-volume production run, our engineers match the elastomer to your fluid, temperature and pressure and build to spec under ISO 9001:2015 and IATF 16949:2016.

AS568 O-Ring Size Chart

The American Rubber Corp Size Reference Chart covers the AS568 O-Ring Sizes published by the Society of Automotive Engineers (S.A.E.), and includes the Extended Sizes in the 400 Series. Dimensional tolerances for all AS568 o-rings offered by American Rubber Corp are in accordance with ISO 3601-1A. The purpose of this chart is to specify the inside diameters, cross-sections, tolerances, and size identification codes (dash numbers) for o-rings used in sealing applications and for straight thread tube fitting boss gaskets.

Need AS568 O-Rings? Standard Sizes or Custom-Made.

American Rubber Corp manufactures every AS568 dash size (-001 through -993) in Silicone, EPDM, FKM (Viton), Nitrile (NBR), HNBR, FFKM, Neoprene, and custom compounds. Standard sizes shipped fast; custom materials made to spec. ISO 9001:2015 + IATF 16949 certified.

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"
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AS568 O-Ring Size Reference Chart

Dash #	CS Nominal	ID Nominal	OD Nominal	CS Inch	ID Inch	Tol Inch	CS mm	ID mm	Tol mm
001	1/32	1/32	3/32	0.04	0.029	± .004	1.02	0.74	± .10
002	3/64	3/64	9/64	0.05	0.042	± .004	1.27	1.07	± .10
003	1/16	1/16	3/16	0.06	0.056	± .004	1.52	1.42	± .10
004	1/16	5/64	13/64	0.07	0.07	± .005	1.78	1.78	± .13
005	1/16	3/32	7/32	0.07	0.101	± .005	1.78	2.57	± .13
006	1/16	1/8	1/4	0.07	0.114	± .005	1.78	2.9	± .13
007	1/16	5/32	9/32	0.07	0.145	± .005	1.78	3.68	± .13
008	1/16	3/16	5/16	0.07	0.176	± .005	1.78	4.47	± .13
009	1/16	7/32	11/32	0.07	0.208	± .005	1.78	5.28	± .13
010	1/16	1/4	3/8	0.07	0.239	± .005	1.78	6.07	± .13
011	1/16	5/16	7/16	0.07	0.301	± .005	1.78	7.65	± .13
012	1/16	3/8	1/2	0.07	0.364	± .005	1.78	9.25	± .13
013	1/16	7/16	9/16	0.07	0.426	± .005	1.78	10.82	± .13
014	1/16	1/2	5/8	0.07	0.489	± .005	1.78	12.42	± .13
015	1/16	9/16	11/16	0.07	0.551	± .007	1.78	14	± .18
016	1/16	5/8	3/4	0.07	0.614	± .009	1.78	15.6	± .23
017	1/16	11/16	13/16	0.07	0.676	± .009	1.78	17.17	± .23
018	1/16	3/4	7/8	0.07	0.739	± .009	1.78	18.77	± .23
019	1/16	13/16	15/16	0.07	0.801	± .009	1.78	20.35	± .23
020	1/16	7/8	1	0.07	0.864	± .009	1.78	21.95	± .23
021	1/16	15/16	1-1/16	0.07	0.926	± .009	1.78	23.52	± .23
022	1/16	1	1-1/8	0.07	0.989	± .010	1.78	25.12	± .25
023	1/16	1-1/16	1-3/16	0.07	1.051	± .010	1.78	26.7	± .25
024	1/16	1-1/8	1-1/4	0.07	1.114	± .010	1.78	28.3	± .25
025	1/16	1-3/16	1-5/16	0.07	1.176	± .011	1.78	29.87	± .28
026	1/16	1-1/4	1-3/8	0.07	1.239	± .011	1.78	31.47	± .28
027	1/16	1-5/16	1-7/16	0.07	1.301	± .011	1.78	33.05	± .28
028	1/16	1-3/8	1-1/2	0.07	1.364	± .013	1.78	34.65	± .33
029	1/16	1-1/2	1-5/8	0.07	1.489	± .013	1.78	37.82	± .33
030	1/16	1-5/8	1-3/4	0.07	1.614	± .013	1.78	41	± .33
031	1/16	1-3/4	1-7/8	0.07	1.739	± .015	1.78	44.17	± .38
032	1/16	1-7/8	2	0.07	1.864	± .015	1.78	47.35	± .38
033	1/16	2	2-1/8	0.07	1.989	± .018	1.78	50.52	± .46
034	1/16	2-1/8	2-1/4	0.07	2.114	± .018	1.78	53.7	± .46
035	1/16	2-1/4	2-3/8	0.07	2.239	± .018	1.78	56.87	± .46
036	1/16	2-3/8	2-1/2	0.07	2.364	± .018	1.78	60.05	± .46
037	1/16	2-1/2	2-5/8	0.07	2.489	± .018	1.78	63.22	± .46
038	1/16	2-5/8	2-3/4	0.07	2.614	± .020	1.78	66.4	± .51
039	1/16	2-3/4	2-7/8	0.07	2.739	± .020	1.78	69.57	± .51
040	1/16	2-7/8	3	0.07	2.864	± .020	1.78	72.75	± .51
041	1/16	3	3-1/8	0.07	2.989	± .024	1.78	75.92	± .61
042	1/16	3-1/4	3-3/8	0.07	3.239	± .024	1.78	82.27	± .61
043	1/16	3-1/2	3-5/8	0.07	3.489	± .024	1.78	88.62	± .61
044	1/16	3-3/4	3-7/8	0.07	3.739	± .027	1.78	94.97	± .69
045	1/16	4	4-1/8	0.07	3.989	± .027	1.78	101.32	± .69
046	1/16	4-1/4	4-3/8	0.07	4.239	± .030	1.78	107.67	± .76
047	1/16	4-1/2	4-5/8	0.07	4.489	± .030	1.78	114.02	± .76
048	1/16	4-3/4	4-7/8	0.07	4.739	± .030	1.78	120.37	± .76
049	1/16	5	5-1/8	0.07	4.989	± .037	1.78	126.72	± .94
050	1/16	5-1/4	5-3/8	0.07	5.239	± .037	1.78	133.07	± .94
102	3/32	1/16	1/4	0.103	0.049	± .005	2.62	1.24	± .13
103	3/32	3/32	9/32	0.103	0.081	± .005	2.62	2.06	± .13
104	3/32	1/8	5/16	0.103	0.112	± .005	2.62	2.84	± .13
105	3/32	5/32	11/32	0.103	0.143	± .005	2.62	3.63	± .13
106	3/32	3/16	3/8	0.103	0.174	± .005	2.62	4.42	± .13
107	3/32	7/32	13/32	0.103	0.206	± .005	2.62	5.23	± .13
108	3/32	1/4	7/16	0.103	0.237	± .005	2.62	6.02	± .13
109	3/32	5/16	1/2	0.103	0.299	± .005	2.62	7.59	± .13
110	3/32	3/8	9/16	0.103	0.362	± .005	2.62	9.19	± .13
111	3/32	7/16	5/8	0.103	0.424	± .005	2.62	10.77	± .13
112	3/32	1/2	11/16	0.103	0.487	± .005	2.62	12.37	± .13
113	3/32	9/16	3/4	0.103	0.549	± .007	2.62	13.94	± .18
114	3/32	5/8	13/16	0.103	0.612	± .009	2.62	15.54	± .23
115	3/32	11/16	7/8	0.103	0.674	± .009	2.62	17.12	± .23
116	3/32	3/4	15/16	0.103	0.737	± .009	2.62	18.72	± .23
117	3/32	13/16	1	0.103	0.799	± .010	2.62	20.29	± .25
118	3/32	7/8	1-1/16	0.103	0.862	± .010	2.62	21.89	± .25
119	3/32	15/16	1-1/8	0.103	0.924	± .010	2.62	23.47	± .25
120	3/32	1	1-3/16	0.103	0.987	± .010	2.62	25.07	± .25
121	3/32	1-1/16	1-1/4	0.103	1.049	± .010	2.62	26.64	± .25
122	3/32	1-1/8	1-5/16	0.103	1.112	± .010	2.62	28.24	± .25
123	3/32	1-3/16	1-3/8	0.103	1.174	± .012	2.62	29.82	± .30
124	3/32	1-1/4	1-7/16	0.103	1.237	± .012	2.62	31.42	± .30
125	3/32	1-5/16	1-1/2	0.103	1.299	± .012	2.62	32.99	± .30
126	3/32	1-3/8	1-9/16	0.103	1.362	± .012	2.62	34.59	± .30
127	3/32	1-7/16	1-5/8	0.103	1.424	± .012	2.62	36.17	± .30
128	3/32	1-1/2	1-11/16	0.103	1.487	± .012	2.62	37.77	± .30
129	3/32	1-9/16	1-3/4	0.103	1.549	± .015	2.62	39.34	± .38
130	3/32	1-5/8	1-13/16	0.103	1.612	± .015	2.62	40.94	± .38
131	3/32	1-11/16	1-7/8	0.103	1.674	± .015	2.62	42.52	± .38
132	3/32	1-3/4	1-15/16	0.103	1.737	± .015	2.62	44.12	± .38
133	3/32	1-13/16	2	0.103	1.799	± .015	2.62	45.69	± .38
134	3/32	1-7/8	2-1/16	0.103	1.862	± .015	2.62	47.29	± .38
135	3/32	1-15/16	2-1/8	0.103	1.925	± .017	2.62	48.9	± .43
136	3/32	2	2-3/16	0.103	1.987	± .017	2.62	50.47	± .43
137	3/32	2-1/16	2-1/4	0.103	2.05	± .017	2.62	52.07	± .43
138	3/32	2-1/8	2-5/16	0.103	2.112	± .017	2.62	53.64	± .43
139	3/32	2-3/16	2-3/8	0.103	2.175	± .017	2.62	55.25	± .43
140	3/32	2-1/4	2-7/16	0.103	2.237	± .017	2.62	56.82	± .43
141	3/32	2-5/16	2-1/2	0.103	2.3	± .020	2.62	58.42	± .51
142	3/32	2-3/8	2-9/16	0.103	2.362	± .020	2.62	59.99	± .51
143	3/32	2-7/16	2-5/8	0.103	2.425	± .020	2.62	61.6	± .51
144	3/32	2-1/2	2-11/16	0.103	2.487	± .020	2.62	63.17	± .51
145	3/32	2-9/16	2-3/4	0.103	2.55	± .020	2.62	64.77	± .51
146	3/32	2-5/8	2-13/16	0.103	2.612	± .020	2.62	66.34	± .51
147	3/32	2-11/16	2-7/8	0.103	2.675	± .022	2.62	67.95	± .56
148	3/32	2-3/4	2-15/16	0.103	2.737	± .022	2.62	69.52	± .56
149	3/32	2-13/16	3	0.103	2.8	± .022	2.62	71.12	± .56
150	3/32	2-7/8	3-1/16	0.103	2.862	± .022	2.62	72.69	± .56
151	3/32	3	3-3/16	0.103	2.987	± .024	2.62	75.87	± .61
152	3/32	3-1/4	3-7/16	0.103	3.237	± .024	2.62	82.22	± .61
153	3/32	3-1/2	3-11/16	0.103	3.487	± .024	2.62	88.57	± .61
154	3/32	3-3/4	3-15/16	0.103	3.737	± .028	2.62	94.92	± .71
155	3/32	4	4-3/16	0.103	3.987	± .028	2.62	101.27	± .71
156	3/32	4-1/4	4-7/16	0.103	4.237	± .030	2.62	107.62	± .76
157	3/32	4-1/2	4-11/16	0.103	4.487	± .030	2.62	113.97	± .76
158	3/32	4-3/4	4-15/16	0.103	4.737	± .030	2.62	120.32	± .76
159	3/32	5	5-3/16	0.103	4.987	± .035	2.62	126.67	± .89
160	3/32	5-1/4	5-7/16	0.103	5.237	± .035	2.62	133.02	± .89
161	3/32	5-1/2	5-11/16	0.103	5.487	± .035	2.62	139.37	± .89
162	3/32	5-3/4	5-15/16	0.103	5.737	± .035	2.62	145.72	± .89
163	3/32	6	6-3/16	0.103	5.987	± .035	2.62	152.07	± .89
164	3/32	6-1/4	6-7/16	0.103	6.237	± .040	2.62	158.42	± 1.02
165	3/32	6-1/2	6-11/16	0.103	6.487	± .040	2.62	164.77	± 1.02
166	3/32	6-3/4	6-15/16	0.103	6.737	± .040	2.62	171.12	± 1.02
167	3/32	7	7-3/16	0.103	6.987	± .040	2.62	177.47	± 1.02
168	3/32	7-1/4	7-7/16	0.103	7.237	± .045	2.62	183.82	± 1.14
169	3/32	7-1/2	7-11/16	0.103	7.487	± .045	2.62	190.17	± 1.14
170	3/32	7-3/4	7-15/16	0.103	7.737	± .045	2.62	196.52	± 1.14
171	3/32	8	8-3/16	0.103	7.987	± .045	2.62	202.87	± 1.14
172	3/32	8-1/4	8-7/16	0.103	8.237	± .050	2.62	209.22	± 1.27
173	3/32	8-1/2	8-11/16	0.103	8.487	± .050	2.62	215.57	± 1.27
174	3/32	8-3/4	8-15/16	0.103	8.737	± .050	2.62	221.92	± 1.27
175	3/32	9	9-3/16	0.103	8.987	± .050	2.62	228.27	± 1.27
176	3/32	9-1/4	9-7/16	0.103	9.237	± .055	2.62	234.62	± 1.40
177	3/32	9-1/2	9-11/16	0.103	9.487	± .055	2.62	240.97	± 1.40
178	3/32	9-3/4	9-15/16	0.103	9.737	± .055	2.62	247.32	± 1.40
201	1/8	3/16	7/16	0.139	0.171	± .005	3.53	4.34	± .13
202	1/8	1/4	1/2	0.139	0.234	± .005	3.53	5.94	± .13
203	1/8	5/16	9/16	0.139	0.296	± .005	3.53	7.52	± .13
204	1/8	3/8	5/8	0.139	0.359	± .005	3.53	9.12	± .13
205	1/8	7/16	11/16	0.139	0.421	± .005	3.53	10.69	± .13
206	1/8	1/2	3/4	0.139	0.484	± .005	3.53	12.29	± .13
207	1/8	9/16	13/16	0.139	0.546	± .007	3.53	13.87	± .18
208	1/8	5/8	7/8	0.139	0.609	± .009	3.53	15.47	± .23
209	1/8	11/16	15/16	0.139	0.671	± .009	3.53	17.04	± .23
210	1/8	3/4	1	0.139	0.734	± .010	3.53	18.64	± .25
211	1/8	13/16	1-1/16	0.139	0.796	± .010	3.53	20.22	± .25
212	1/8	7/8	1-1/8	0.139	0.859	± .010	3.53	21.82	± .25
213	1/8	15/16	1-3/16	0.139	0.921	± .010	3.53	23.39	± .25
214	1/8	1	1-1/4	0.139	0.984	± .010	3.53	24.99	± .25
215	1/8	1-1/16	1-5/16	0.139	1.046	± .010	3.53	26.57	± .25
216	1/8	1-1/8	1-3/8	0.139	1.109	± .012	3.53	28.17	± .30
217	1/8	1-3/16	1-7/16	0.139	1.171	± .012	3.53	29.74	± .30
218	1/8	1-1/4	1-1/2	0.139	1.234	± .012	3.53	31.34	± .30
219	1/8	1-5/16	1-9/16	0.139	1.296	± .012	3.53	32.92	± .30
220	1/8	1-3/8	1-5/8	0.139	1.359	± .012	3.53	34.52	± .30
221	1/8	1-7/16	1-11/16	0.139	1.421	± .012	3.53	36.09	± .30
222	1/8	1-1/2	1-3/4	0.139	1.484	± .015	3.53	37.69	± .38
223	1/8	1-5/8	1-7/8	0.139	1.609	± .015	3.53	40.87	± .38
224	1/8	1-3/4	2	0.139	1.734	± .015	3.53	44.04	± .38
225	1/8	1-7/8	2-1/8	0.139	1.859	± .018	3.53	47.22	± .46
226	1/8	2	2-1/4	0.139	1.984	± .018	3.53	50.39	± .46
227	1/8	2-1/8	2-3/8	0.139	2.109	± .018	3.53	53.57	± .46
228	1/8	2-1/4	2-1/2	0.139	2.234	± .020	3.53	56.74	± .51
229	1/8	2-3/8	2-5/8	0.139	2.359	± .020	3.53	59.92	± .51
230	1/8	2-1/2	2-3/4	0.139	2.484	± .020	3.53	63.09	± .51
231	1/8	2-5/8	2-7/8	0.139	2.609	± .020	3.53	66.27	± .51
232	1/8	2-3/4	3	0.139	2.734	± .024	3.53	69.44	± .61
233	1/8	2-7/8	3-1/8	0.139	2.859	± .024	3.53	72.62	± .61
234	1/8	3	3-1/4	0.139	2.984	± .024	3.53	75.79	± .61
235	1/8	3-1/8	3-3/8	0.139	3.109	± .024	3.53	78.97	± .61
236	1/8	3-1/4	3-1/2	0.139	3.234	± .024	3.53	82.14	± .61
237	1/8	3-3/8	3-5/8	0.139	3.359	± .024	3.53	85.32	± .61
238	1/8	3-1/2	3-3/4	0.139	3.484	± .024	3.53	88.49	± .61
239	1/8	3-5/8	3-7/8	0.139	3.609	± .028	3.53	91.67	± .71
240	1/8	3-3/4	4	0.139	3.734	± .028	3.53	94.84	± .71
241	1/8	3-7/8	4-1/8	0.139	3.859	± .028	3.53	98.02	± .71
242	1/8	4	4-1/4	0.139	3.984	± .028	3.53	101.19	± .71
243	1/8	4-1/8	4-3/8	0.139	4.109	± .028	3.53	104.37	± .71
244	1/8	4-1/4	4-1/2	0.139	4.234	± .030	3.53	107.54	± .76
245	1/8	4-3/8	4-5/8	0.139	4.359	± .030	3.53	110.72	± .76
246	1/8	4-1/2	4-3/4	0.139	4.484	± .030	3.53	113.89	± .76
247	1/8	4-5/8	4-7/8	0.139	4.609	± .030	3.53	117.07	± .76
248	1/8	4-3/4	5	0.139	4.734	± .030	3.53	120.24	± .76
249	1/8	4-7/8	5-1/8	0.139	4.859	± .035	3.53	123.42	± .89
250	1/8	5	5-1/4	0.139	4.984	± .035	3.53	126.59	± .89
251	1/8	5-1/8	5-3/8	0.139	5.109	± .035	3.53	129.77	± .89
252	1/8	5-1/4	5-1/2	0.139	5.234	± .035	3.53	132.94	± .89
253	1/8	5-3/8	5-5/8	0.139	5.359	± .035	3.53	136.12	± .89
254	1/8	5-1/2	5-3/4	0.139	5.484	± .035	3.53	139.29	± .89
255	1/8	5-5/8	5-7/8	0.139	5.609	± .035	3.53	142.47	± .89
256	1/8	5-3/4	6	0.139	5.734	± .035	3.53	145.64	± .89
257	1/8	5-7/8	6-1/8	0.139	5.859	± .035	3.53	148.82	± .89
258	1/8	6	6-1/4	0.139	5.984	± .035	3.53	151.99	± .89
259	1/8	6-1/4	6-1/2	0.139	6.234	± .040	3.53	158.34	± 1.02
260	1/8	6-1/2	6-3/4	0.139	6.484	± .040	3.53	164.69	± 1.02
261	1/8	6-3/4	7	0.139	6.734	± .040	3.53	171.04	± 1.02
262	1/8	7	7-1/4	0.139	6.984	± .040	3.53	177.39	± 1.02
263	1/8	7-1/4	7-1/2	0.139	7.234	± .045	3.53	183.74	± 1.14
264	1/8	7-1/2	7-3/4	0.139	7.484	± .045	3.53	190.09	± 1.14
265	1/8	7-3/4	8	0.139	7.734	± .045	3.53	196.44	± 1.14
266	1/8	8	8-1/4	0.139	7.984	± .045	3.53	202.79	± 1.14
267	1/8	8-1/4	8-1/2	0.139	8.234	± .050	3.53	209.14	± 1.27
268	1/8	8-1/2	8-3/4	0.139	8.484	± .050	3.53	215.49	± 1.27
269	1/8	8-3/4	9	0.139	8.734	± .050	3.53	221.84	± 1.27
270	1/8	9	9-1/4	0.139	8.984	± .050	3.53	228.19	± 1.27
271	1/8	9-1/4	9-1/2	0.139	9.234	± .055	3.53	234.54	± 1.40
272	1/8	9-1/2	9-3/4	0.139	9.484	± .055	3.53	240.89	± 1.40
273	1/8	9-3/4	10	0.139	9.734	± .055	3.53	247.24	± 1.40
274	1/8	10	10-1/4	0.139	9.984	± .055	3.53	253.59	± 1.40
275	1/8	10-1/2	10-3/4	0.139	10.484	± .055	3.53	266.29	± 1.40
276	1/8	11	11-1/4	0.139	10.984	± .065	3.53	278.99	± 1.65
277	1/8	11-1/2	11-3/4	0.139	11.484	± .065	3.53	291.69	± 1.65
278	1/8	12	12-1/4	0.139	11.984	± .065	3.53	304.39	± 1.65
279	1/8	13	13-1/4	0.139	12.984	± .065	3.53	329.79	± 1.65
280	1/8	14	14-1/4	0.139	13.984	± .065	3.53	355.19	± 1.65
281	1/8	15	15-1/4	0.139	14.984	± .065	3.53	380.59	± 1.65
282	1/8	16	16-1/4	0.139	15.955	± .075	3.53	405.26	± 1.91
283	1/8	17	17-1/4	0.139	16.955	± .080	3.53	430.66	± 2.03
284	1/8	18	18-1/4	0.139	17.955	± .085	3.53	456.06	± 2.16
309	3/16	7/16	13/16	0.21	0.412	± .005	5.33	10.46	± .13
310	3/16	1/2	7/8	0.21	0.475	± .005	5.33	12.07	± .13
311	3/16	9/16	15/16	0.21	0.537	± .007	5.33	13.64	± .18
312	3/16	5/8	1	0.21	0.6	± .009	5.33	15.24	± .23
313	3/16	11/16	1-1/16	0.21	0.662	± .009	5.33	16.81	± .23
314	3/16	3/4	1-1/8	0.21	0.725	± .010	5.33	18.42	± .25
315	3/16	13/16	1-3/16	0.21	0.787	± .010	5.33	19.99	± .25
316	3/16	7/8	1-1/4	0.21	0.85	± .010	5.33	21.59	± .25
317	3/16	15/16	1-5/16	0.21	0.912	± .010	5.33	23.16	± .25
318	3/16	1	1-3/8	0.21	0.975	± .010	5.33	24.77	± .25
319	3/16	1-1/16	1-7/16	0.21	1.037	± .010	5.33	26.34	± .25
320	3/16	1-1/8	1-1/2	0.21	1.1	± .012	5.33	27.94	± .30
321	3/16	1-3/16	1-9/16	0.21	1.162	± .012	5.33	29.51	± .30
322	3/16	1-1/4	1-5/8	0.21	1.225	± .012	5.33	31.12	± .30
323	3/16	1-5/16	1-11/16	0.21	1.287	± .012	5.33	32.69	± .30
324	3/16	1-3/8	1-3/4	0.21	1.35	± .012	5.33	34.29	± .30
325	3/16	1-1/2	1-7/8	0.21	1.475	± .015	5.33	37.47	± .38
326	3/16	1-5/8	2	0.21	1.6	± .015	5.33	40.64	± .38
327	3/16	1-3/4	2-1/8	0.21	1.725	± .015	5.33	43.82	± .38
328	3/16	1-7/8	2-1/4	0.21	1.85	± .015	5.33	46.99	± .38
329	3/16	2	2-3/8	0.21	1.975	± .018	5.33	50.17	± .46
330	3/16	2-1/8	2-1/2	0.21	2.1	± .018	5.33	53.34	± .46
331	3/16	2-1/4	2-5/8	0.21	2.225	± .018	5.33	56.52	± .46
332	3/16	2-3/8	2-3/4	0.21	2.35	± .018	5.33	59.69	± .46
333	3/16	2-1/2	2-7/8	0.21	2.475	± .020	5.33	62.87	± .51
334	3/16	2-5/8	3	0.21	2.6	± .020	5.33	66.04	± .51
335	3/16	2-3/4	3-1/8	0.21	2.725	± .020	5.33	69.22	± .51
336	3/16	2-7/8	3-1/4	0.21	2.85	± .020	5.33	72.39	± .51
337	3/16	3	3-3/8	0.21	2.975	± .024	5.33	75.57	± .61
338	3/16	3-1/8	3-1/2	0.21	3.1	± .024	5.33	78.74	± .61
339	3/16	3-1/4	3-5/8	0.21	3.225	± .024	5.33	81.92	± .61
340	3/16	3-3/8	3-3/4	0.21	3.35	± .024	5.33	85.09	± .61
341	3/16	3-1/2	3-7/8	0.21	3.475	± .024	5.33	88.27	± .61
342	3/16	3-5/8	4	0.21	3.6	± .028	5.33	91.44	± .71
343	3/16	3-3/4	4-1/8	0.21	3.725	± .028	5.33	94.62	± .71
344	3/16	3-7/8	4-1/4	0.21	3.85	± .028	5.33	97.79	± .71
345	3/16	4	4-3/8	0.21	3.975	± .028	5.33	100.97	± .71
346	3/16	4-1/8	4-1/2	0.21	4.1	± .028	5.33	104.14	± .71
347	3/16	4-1/4	4-5/8	0.21	4.225	± .030	5.33	107.32	± .76
348	3/16	4-3/8	4-3/4	0.21	4.35	± .030	5.33	110.49	± .76
349	3/16	4-1/2	4-7/8	0.21	4.475	± .030	5.33	113.67	± .76
350	3/16	4-5/8	5	0.21	4.6	± .030	5.33	116.84	± .76
351	3/16	4-3/4	5-1/8	0.21	4.725	± .030	5.33	120.02	± .76
352	3/16	4-7/8	5-1/4	0.21	4.85	± .030	5.33	123.19	± .76
353	3/16	5	5-3/8	0.21	4.975	± .037	5.33	126.37	± .94
354	3/16	5-1/8	5-1/2	0.21	5.1	± .037	5.33	129.54	± .94
355	3/16	5-1/4	5-5/8	0.21	5.225	± .037	5.33	132.72	± .94
356	3/16	5-3/8	5-3/4	0.21	5.35	± .037	5.33	135.89	± .94
357	3/16	5-1/2	5-7/8	0.21	5.475	± .037	5.33	139.07	± .94
358	3/16	5-5/8	6	0.21	5.6	± .037	5.33	142.24	± .94
359	3/16	5-3/4	6-1/8	0.21	5.725	± .037	5.33	145.42	± .94
360	3/16	5-7/8	6-1/4	0.21	5.85	± .037	5.33	148.59	± .94
361	3/16	6	6-3/8	0.21	5.975	± .037	5.33	151.77	± .94
362	3/16	6-1/4	6-5/8	0.21	6.225	± .040	5.33	158.12	± 1.02
363	3/16	6-1/2	6-7/8	0.21	6.475	± .040	5.33	164.47	± 1.02
364	3/16	6-3/4	7-1/8	0.21	6.725	± .040	5.33	170.82	± 1.02
365	3/16	7	7-3/8	0.21	6.975	± .040	5.33	177.17	± 1.02
366	3/16	7-1/4	7-5/8	0.21	7.225	± .045	5.33	183.52	± 1.14
367	3/16	7-1/2	7-7/8	0.21	7.475	± .045	5.33	189.87	± 1.14
368	3/16	7-3/4	8-1/8	0.21	7.725	± .045	5.33	196.22	± 1.14
369	3/16	8	8-3/8	0.21	7.975	± .045	5.33	202.57	± 1.14
370	3/16	8-1/4	8-5/8	0.21	8.225	± .050	5.33	208.92	± 1.27
371	3/16	8-1/2	8-7/8	0.21	8.475	± .050	5.33	215.27	± 1.27
372	3/16	8-3/4	9-1/8	0.21	8.725	± .050	5.33	221.62	± 1.27
373	3/16	9	9-3/8	0.21	8.975	± .050	5.33	227.97	± 1.27
374	3/16	9-1/4	9-5/8	0.21	9.225	± .055	5.33	234.32	± 1.40
375	3/16	9-1/2	9-7/8	0.21	9.475	± .055	5.33	240.67	± 1.40
376	3/16	9-3/4	10-1/8	0.21	9.725	± .055	5.33	247.02	± 1.40
377	3/16	10	10-3/8	0.21	9.975	± .055	5.33	253.37	± 1.40
378	3/16	10-1/2	10-7/8	0.21	10.475	± .060	5.33	266.07	± 1.52
379	3/16	11	11-3/8	0.21	10.975	± .060	5.33	278.77	± 1.52
380	3/16	11-1/2	11-7/8	0.21	11.475	± .065	5.33	291.47	± 1.65
381	3/16	12	12-3/8	0.21	11.975	± .065	5.33	304.17	± 1.65
382	3/16	13	13-3/8	0.21	12.975	± .065	5.33	329.57	± 1.65
383	3/16	14	14-3/8	0.21	13.975	± .070	5.33	354.97	± 1.78
384	3/16	15	15-3/8	0.21	14.975	± .070	5.33	380.37	± 1.78
385	3/16	16	16-3/8	0.21	15.955	± .075	5.33	405.26	± 1.91
386	3/16	17	17-3/8	0.21	16.955	± .080	5.33	430.66	± 2.03
387	3/16	18	18-3/8	0.21	17.955	± .085	5.33	456.06	± 2.16
388	3/16	19	19-3/8	0.21	18.955	± .090	5.33	481.46	± 2.29
389	3/16	20	20-3/8	0.21	19.955	± .095	5.33	506.86	± 2.41
390	3/16	21	21-3/8	0.21	20.955	± .095	5.33	532.26	± 2.41
391	3/16	22	22-3/8	0.21	21.955	± .095	5.33	557.66	± 2.41
392	3/16	23	23-3/8	0.21	22.94	± .105	5.33	582.68	± 2.67
393	3/16	24	24-3/8	0.21	23.94	± .110	5.33	608.08	± 2.79
394	3/16	25	25-3/8	0.21	24.94	± .115	5.33	633.48	± 2.92
395	3/16	26	26-3/8	0.21	25.94	± .120	5.33	658.88	± 3.05
400	1/4	1-3/8	1-7/8	0.275	1.35	± .012	6.99	34.29	± .30
401	1/4	1-1/2	2	0.275	1.475	± .015	6.99	37.47	± .38
402	1/4	1-5/8	2-1/8	0.275	1.6	± .015	6.99	40.64	± .38
403	1/4	1-3/4	2-1/4	0.275	1.725	± .015	6.99	43.82	± .38
404	1/4	1-7/8	2-3/8	0.275	1.85	± .015	6.99	46.99	± .38
405	1/4	2	2-1/2	0.275	1.975	± .018	6.99	50.17	± .46
406	1/4	2-1/8	2-5/8	0.275	2.1	± .018	6.99	53.34	± .46
407	1/4	2-1/4	2-3/4	0.275	2.225	± .018	6.99	56.52	± .46
408	1/4	2-3/8	2-7/8	0.275	2.35	± .018	6.99	59.69	± .46
409	1/4	2-1/2	3	0.275	2.475	± .020	6.99	62.87	± .51
410	1/4	2-5/8	3-1/8	0.275	2.6	± .020	6.99	66.04	± .51
411	1/4	2-3/4	3-1/4	0.275	2.725	± .020	6.99	69.22	± .51
412	1/4	2-7/8	3-3/8	0.275	2.85	± .020	6.99	72.39	± .51
413	1/4	3	3-1/2	0.275	2.975	± .024	6.99	75.57	± .61
414	1/4	3-1/8	3-5/8	0.275	3.1	± .024	6.99	78.74	± .61
415	1/4	3-1/4	3-3/4	0.275	3.225	± .024	6.99	81.92	± .61
416	1/4	3-3/8	3-7/8	0.275	3.35	± .024	6.99	85.09	± .61
417	1/4	3-1/2	4	0.275	3.475	± .024	6.99	88.27	± .61
418	1/4	3-5/8	4-1/8	0.275	3.6	± .028	6.99	91.44	± .71
419	1/4	3-3/4	4-1/4	0.275	3.725	± .028	6.99	94.62	± .71
420	1/4	3-7/8	4-3/8	0.275	3.85	± .028	6.99	97.79	± .71
421	1/4	4	4-1/2	0.275	3.975	± .028	6.99	100.97	± .71
422	1/4	4-1/8	4-5/8	0.275	4.1	± .028	6.99	104.14	± .71
423	1/4	4-1/4	4-3/4	0.275	4.225	± .030	6.99	107.32	± .76
424	1/4	4-3/8	4-7/8	0.275	4.35	± .030	6.99	110.49	± .76
425	1/4	4-1/2	5	0.275	4.475	± .033	6.99	113.67	± .84
426	1/4	4-5/8	5-1/8	0.275	4.6	± .033	6.99	116.84	± .84
427	1/4	4-3/4	5-1/4	0.275	4.725	± .033	6.99	120.02	± .84
428	1/4	4-7/8	5-3/8	0.275	4.85	± .033	6.99	123.19	± .84
429	1/4	5	5-1/2	0.275	4.975	± .037	6.99	126.37	± .94
430	1/4	5-1/8	5-5/8	0.275	5.1	± .037	6.99	129.54	± .94
431	1/4	5-1/4	5-3/4	0.275	5.225	± .037	6.99	132.72	± .94
432	1/4	5-3/8	5-7/8	0.275	5.35	± .037	6.99	135.89	± .94
433	1/4	5-1/2	6	0.275	5.475	± .037	6.99	139.07	± .94
434	1/4	5-5/8	6-1/8	0.275	5.6	± .037	6.99	142.24	± .94
435	1/4	5-3/4	6-1/4	0.275	5.725	± .037	6.99	145.42	± .94
436	1/4	5-7/8	6-3/8	0.275	5.85	± .037	6.99	148.59	± .94
437	1/4	6	6-1/2	0.275	5.975	± .037	6.99	151.77	± .94
438	1/4	6-1/4	6-3/4	0.275	6.225	± .040	6.99	158.12	± 1.02
439	1/4	6-1/2	7	0.275	6.475	± .040	6.99	164.47	± 1.02
440	1/4	6-3/4	7-1/4	0.275	6.725	± .040	6.99	170.82	± 1.02
441	1/4	7	7-1/2	0.275	6.975	± .040	6.99	177.17	± 1.02
442	1/4	7-1/4	7-3/4	0.275	7.225	± .045	6.99	183.52	± 1.14
443	1/4	7-1/2	8	0.275	7.475	± .045	6.99	189.87	± 1.14
444	1/4	7-3/4	8-1/4	0.275	7.725	± .045	6.99	196.22	± 1.14
445	1/4	8	8-1/2	0.275	7.975	± .045	6.99	202.57	± 1.14
446	1/4	8-1/2	9	0.275	8.475	± .055	6.99	215.27	± 1.40
447	1/4	9	9-1/2	0.275	8.975	± .055	6.99	227.97	± 1.40
448	1/4	9-1/2	10	0.275	9.475	± .055	6.99	240.67	± 1.40
449	1/4	10	10-1/2	0.275	9.975	± .055	6.99	253.37	± 1.40
450	1/4	10-1/2	11	0.275	10.475	± .060	6.99	266.07	± 1.52
451	1/4	11	11-1/2	0.275	10.975	± .060	6.99	278.77	± 1.52
452	1/4	11-1/2	12	0.275	11.475	± .060	6.99	291.47	± 1.52
453	1/4	12	12-1/2	0.275	11.975	± .060	6.99	304.17	± 1.52
454	1/4	12-1/2	13	0.275	12.475	± .060	6.99	316.87	± 1.52
455	1/4	13	13-1/2	0.275	12.975	± .060	6.99	329.57	± 1.52
456	1/4	13-1/2	14	0.275	13.475	± .070	6.99	342.27	± 1.78
457	1/4	14	14-1/2	0.275	13.975	± .070	6.99	354.97	± 1.78
458	1/4	14-1/2	15	0.275	14.475	± .070	6.99	367.67	± 1.78
459	1/4	15	15-1/2	0.275	14.975	± .070	6.99	380.37	± 1.78
460	1/4	15-1/2	16	0.275	15.475	± .070	6.99	393.07	± 1.78
461	1/4	16	16-1/2	0.275	15.955	± .075	6.99	405.26	± 1.91
462	1/4	16-1/2	17	0.275	16.455	± .075	6.99	417.96	± 1.91
463	1/4	17	17-1/2	0.275	16.955	± .080	6.99	430.66	± 2.03
464	1/4	17-1/2	18	0.275	17.455	± .085	6.99	443.36	± 2.16
465	1/4	18	18-1/2	0.275	17.955	± .085	6.99	456.06	± 2.16
466	1/4	18-1/2	19	0.275	18.455	± .085	6.99	468.76	± 2.16
467	1/4	19	19-1/2	0.275	18.955	± .090	6.99	481.46	± 2.29
468	1/4	19-1/2	20	0.275	19.455	± .090	6.99	494.16	± 2.29
469	1/4	20	20-1/2	0.275	19.955	± .095	6.99	506.86	± 2.41
470	1/4	21	21-1/2	0.275	20.955	± .095	6.99	532.26	± 2.41
471	1/4	22	22-1/2	0.275	21.955	± .100	6.99	557.66	± 2.54
472	1/4	23	23-1/2	0.275	22.94	± .105	6.99	582.68	± 2.67
473	1/4	24	24-1/2	0.275	23.94	± .110	6.99	608.08	± 2.79
474	1/4	25	25-1/2	0.275	24.94	± .115	6.99	633.48	± 2.92
475	1/4	26	26-1/2	0.275	25.94	± .120	6.99	658.88	± 3.05
901				0.056	0.185	± .005	1.42	4.7	± .13
902				0.064	0.239	± .005	1.63	6.07	± .13
903				0.064	0.301	± .005	1.63	7.65	± .13
904				0.072	0.351	± .005	1.83	8.92	± .13
905				0.072	0.414	± .005	1.83	10.52	± .13
906				0.078	0.468	± .005	1.98	11.89	± .13
907				0.082	0.53	± .007	2.08	13.46	± .18
908				0.087	0.644	± .009	2.21	16.36	± .23
909				0.097	0.706	± .009	2.46	17.93	± .23
910				0.097	0.755	± .009	2.46	19.18	± .23
911				0.116	0.863	± .009	2.95	21.92	± .23
912				0.116	0.924	± .009	2.95	23.47	± .23
913				0.116	0.986	± .010	2.95	25.04	± .25
914				0.116	1.047	± .010	2.95	26.59	± .25
916				0.116	1.171	± .010	2.95	29.74	± .25
918				0.116	1.355	± .012	2.95	34.42	± .30
920				0.118	1.475	± .014	3	37.47	± .36
924				0.118	1.72	± .014	3	43.69	± .36
928				0.118	2.09	± .018	3	53.09	± .46
932				0.118	2.337	± .018	3	59.36	± .46
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History

This size chart was first published in 1971 by the A-6c2 Seals Committee at SAE (Society of Automotive Engineers) as Aerospace Standard AS568. These standards were later republished in 1974 as AS568A, in 2001 as AS568B, in 2008 as AS568C, and most recently in 2014 as AS568D. Any of these terms (AS568, AS568A, AS568B, AS568C, AS568D) may be used interchangeably when referring to an o-ring dash size.

Looking for an AS568 Equivalent in Metric or Another Standard?

Use our Cross-Reference Table to find AS568 equivalents in ISO 3601, BS 1806, DIN 3771, JIS B 2401, SMS 1586, or NF T 47-501. Or request a quote and we’ll cross-reference for you.

Actual vs. Nominal

To assist our customers in selecting the correct size o-ring we have included 3 measurements for cross reference purposes; the “Nominal”, “Actual Inch”, and “Actual Metric” sizes. We are often asked, “What is the difference between Actual and Nominal sizes for o-rings?”. The Nominal (fractional) dimensions are in name only (often used when verbally describing the size). For more accurate measurements, please refer to the actual inch or millimeter sizes, as these are the true dimensions of the o-ring.

O-Ring Formulas

To calculate an o-ring’s outside diameter (OD) you may use this formula: 2(CS) + ID = OD
Conversely, if you have the OD and need to find the ID use this formula: OD – 2(CS) = ID

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AS568 O-Ring Size Chart

Sourcing AS568 O-rings for your build

AS568 O-Ring Size Chart

Need AS568 O-Rings? Standard Sizes or Custom-Made.

AS568 O-Ring Size Reference Chart

History

Actual vs. Nominal

O-Ring Formulas

Need AS568 O-rings in the right compound?

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