AS568 O-Ring Size Chart: Imperial & Metric

AS568 O-Ring Size Chart | Imperial & Metric Dimensions – Hi-Tech Seals

O-Ring Size Chart & Measurement Guide
This O-ring size chart follows the AS568 standard, the North American industry standard for O-ring dimensions. It provides dash sizes with corresponding inner diameter (I.D.), outer diameter (O.D.), cross-section (C/S), and tolerance values in imperial (inches), along with metric (millimetre) conversions for reference. Whether specifying O-rings for hydraulic, pneumatic, or industrial applications, this reference covers a wide range of standard O-ring dash sizes from the 000 through 400 series.

Dash #: The standard AS568 dash number used to identify each O-ring size. Use this number when ordering to ensure the exact size.
I.D. (Inner Diameter): The inside diameter of the O-ring, used to determine proper fit within the groove or around a rod.
O.D. (Outer Diameter): The outside diameter of the O-ring.
C/S (Cross-Section): The thickness of the O-ring material, measured across the ring.
± TOL. (Tolerance): The acceptable variation in each dimension per AS568 standards.

To quickly identify the correct size, use the search bar to look up by dash number, I.D., or O.D., or filter by C/S series using the buttons below.

DASH #	Nominal			Imperial Actual (inches)				Metric Actual (mm)
DASH #	I.D.	O.D.	C/S	I.D.	± Tol.	C/S	± Tol.	I.D.	± Tol.	C/S	± Tol.
000 SeriesC/S = 1/32" – 1/16" (0.040" – 0.070" / 1.02 – 1.78 mm)
001	1/32	3/32	1/32	0.029	±0.004	0.040	±0.003	0.74	±0.10	1.02	±0.08
002	3/64	9/64	3/64	0.042	±0.004	0.050	±0.003	1.07	±0.10	1.27	±0.08
003	1/16	3/16	1/16	0.056	±0.004	0.060	±0.003	1.42	±0.10	1.52	±0.08
004	5/64	13/64	1/16	0.070	±0.005	0.070	±0.003	1.78	±0.13	1.78	±0.08
005	3/32	7/32	1/16	0.101	±0.005	0.070	±0.003	2.57	±0.13	1.78	±0.08
006	1/8	1/4	1/16	0.114	±0.005	0.070	±0.003	2.90	±0.13	1.78	±0.08
007	5/32	9/32	1/16	0.145	±0.005	0.070	±0.003	3.68	±0.13	1.78	±0.08
008	3/16	5/16	1/16	0.176	±0.005	0.070	±0.003	4.47	±0.13	1.78	±0.08
009	7/32	11/32	1/16	0.208	±0.005	0.070	±0.003	5.28	±0.13	1.78	±0.08
010	1/4	3/8	1/16	0.239	±0.005	0.070	±0.003	6.07	±0.13	1.78	±0.08
011	5/16	7/16	1/16	0.301	±0.005	0.070	±0.003	7.65	±0.13	1.78	±0.08
012	3/8	1/2	1/16	0.364	±0.005	0.070	±0.003	9.25	±0.13	1.78	±0.08
013	7/16	9/16	1/16	0.426	±0.005	0.070	±0.003	10.82	±0.13	1.78	±0.08
014	1/2	5/8	1/16	0.489	±0.005	0.070	±0.003	12.42	±0.13	1.78	±0.08
015	9/16	11/16	1/16	0.551	±0.007	0.070	±0.003	14.00	±0.18	1.78	±0.08
016	5/8	3/4	1/16	0.614	±0.009	0.070	±0.003	15.60	±0.23	1.78	±0.08
017	11/16	13/16	1/16	0.676	±0.009	0.070	±0.003	17.17	±0.23	1.78	±0.08
018	3/4	7/8	1/16	0.739	±0.009	0.070	±0.003	18.77	±0.23	1.78	±0.08
019	13/16	15/16	1/16	0.801	±0.009	0.070	±0.003	20.35	±0.23	1.78	±0.08
020	7/8	1	1/16	0.864	±0.009	0.070	±0.003	21.95	±0.23	1.78	±0.08
021	15/16	1-1/16	1/16	0.926	±0.009	0.070	±0.003	23.52	±0.23	1.78	±0.08
022	1	1-1/8	1/16	0.989	±0.010	0.070	±0.003	25.12	±0.25	1.78	±0.08
023	1-1/16	1-3/16	1/16	1.051	±0.010	0.070	±0.003	26.70	±0.25	1.78	±0.08
024	1-1/8	1-1/4	1/16	1.114	±0.010	0.070	±0.003	28.30	±0.25	1.78	±0.08
025	1-3/16	1-5/16	1/16	1.176	±0.011	0.070	±0.003	29.87	±0.28	1.78	±0.08
026	1-1/4	1-3/8	1/16	1.239	±0.011	0.070	±0.003	31.47	±0.28	1.78	±0.08
027	1-5/16	1-7/16	1/16	1.301	±0.011	0.070	±0.003	33.05	±0.28	1.78	±0.08
028	1-3/8	1-1/2	1/16	1.364	±0.013	0.070	±0.003	34.65	±0.33	1.78	±0.08
029	1-1/2	1-5/8	1/16	1.489	±0.013	0.070	±0.003	37.62	±0.33	1.78	±0.08
030	1-5/8	1-3/4	1/16	1.614	±0.013	0.070	±0.003	41.00	±0.33	1.78	±0.08
031	1-3/4	1-7/8	1/16	1.739	±0.015	0.070	±0.003	44.17	±0.38	1.78	±0.08
032	1-7/8	2	1/16	1.864	±0.015	0.070	±0.003	47.35	±0.38	1.78	±0.08
033	2	2-1/8	1/16	1.989	±0.018	0.070	±0.003	50.25	±0.46	1.78	±0.08
034	2-1/8	2-1/4	1/16	2.114	±0.018	0.070	±0.003	53.70	±0.46	1.78	±0.08
035	2-1/4	2-3/8	1/16	2.239	±0.018	0.070	±0.003	56.87	±0.46	1.78	±0.08
036	2-3/8	2-1/2	1/16	2.364	±0.018	0.070	±0.003	60.05	±0.46	1.78	±0.08
037	2-1/2	2-5/8	1/16	2.489	±0.018	0.070	±0.003	63.22	±0.46	1.78	±0.08
038	2-5/8	2-3/4	1/16	2.614	±0.020	0.070	±0.003	66.40	±0.51	1.78	±0.08
039	2-3/4	2-7/8	1/16	2.739	±0.020	0.070	±0.003	69.57	±0.51	1.78	±0.08
040	2-7/8	3	1/16	2.864	±0.020	0.070	±0.003	72.75	±0.51	1.78	±0.08
041	3	3-1/8	1/16	2.989	±0.024	0.070	±0.003	75.92	±0.61	1.78	±0.08
042	3-1/4	3-3/8	1/16	3.239	±0.024	0.070	±0.003	82.27	±0.61	1.78	±0.08
043	3-1/2	3-5/8	1/16	3.489	±0.024	0.070	±0.003	88.62	±0.61	1.78	±0.08
044	3-3/4	3-7/8	1/16	3.739	±0.027	0.070	±0.003	94.97	±0.69	1.78	±0.08
045	4	4-1/8	1/16	3.989	±0.027	0.070	±0.003	101.32	±0.69	1.78	±0.08
046	4-1/4	4-3/8	1/16	4.239	±0.030	0.070	±0.003	107.67	±0.76	1.78	±0.08
047	4-1/2	4-5/8	1/16	4.489	±0.030	0.070	±0.003	114.02	±0.76	1.78	±0.08
048	4-3/4	4-7/8	1/16	4.739	±0.030	0.070	±0.003	120.37	±0.76	1.78	±0.08
049	5	5-1/8	1/16	4.989	±0.037	0.070	±0.003	126.72	±0.94	1.78	±0.08
050	5-1/4	5-3/8	1/16	5.239	±0.037	0.070	±0.003	133.07	±0.94	1.78	±0.08
100 SeriesC/S = 3/32" (0.103" / 2.62 mm)
102	1/16	1/4	3/32	0.049	±0.005	0.103	±0.003	1.24	±0.13	2.62	±0.08
103	3/32	9/32	3/32	0.081	±0.005	0.103	±0.003	2.06	±0.13	2.62	±0.08
104	1/8	5/16	3/32	0.112	±0.005	0.103	±0.003	2.84	±0.13	2.62	±0.08
105	5/32	11/32	3/32	0.143	±0.005	0.103	±0.003	3.63	±0.13	2.62	±0.08
106	3/16	3/8	3/32	0.174	±0.005	0.103	±0.003	4.42	±0.13	2.62	±0.08
107	7/32	13/32	3/32	0.206	±0.005	0.103	±0.003	5.23	±0.13	2.62	±0.08
108	1/4	7/16	3/32	0.237	±0.005	0.103	±0.003	6.02	±0.13	2.62	±0.08
109	5/16	1/2	3/32	0.299	±0.005	0.103	±0.003	7.59	±0.13	2.62	±0.08
110	3/8	9/16	3/32	0.362	±0.005	0.103	±0.003	9.19	±0.13	2.62	±0.08
111	7/16	5/8	3/32	0.424	±0.005	0.103	±0.003	10.77	±0.13	2.62	±0.08
112	1/2	11/16	3/32	0.487	±0.005	0.103	±0.003	12.37	±0.13	2.62	±0.08
113	9/16	3/4	3/32	0.549	±0.007	0.103	±0.003	13.94	±0.18	2.62	±0.08
114	5/8	13/16	3/32	0.612	±0.009	0.103	±0.003	15.54	±0.23	2.62	±0.08
115	11/16	7/8	3/32	0.674	±0.009	0.103	±0.003	17.12	±0.23	2.62	±0.08
116	3/4	15/16	3/32	0.737	±0.009	0.103	±0.003	18.72	±0.23	2.62	±0.08
117	13/16	1	3/32	0.799	±0.010	0.103	±0.003	20.29	±0.25	2.62	±0.08
118	7/8	1-1/16	3/32	0.862	±0.010	0.103	±0.003	21.89	±0.25	2.62	±0.08
119	15/16	1-1/8	3/32	0.924	±0.010	0.103	±0.003	23.47	±0.25	2.62	±0.08
120	1	1-3/16	3/32	0.987	±0.010	0.103	±0.003	25.07	±0.25	2.62	±0.08
121	1-1/16	1-1/4	3/32	1.049	±0.010	0.103	±0.003	26.64	±0.25	2.62	±0.08
122	1-1/8	1-5/16	3/32	1.112	±0.010	0.103	±0.003	28.24	±0.25	2.62	±0.08
123	1-3/16	1-3/8	3/32	1.174	±0.012	0.103	±0.003	29.82	±0.30	2.62	±0.08
124	1-1/4	1-7/16	3/32	1.237	±0.012	0.103	±0.003	31.42	±0.30	2.62	±0.08
125	1-5/16	1-1/2	3/32	1.299	±0.012	0.103	±0.003	32.99	±0.30	2.62	±0.08
126	1-3/8	1-9/16	3/32	1.362	±0.012	0.103	±0.003	34.59	±0.30	2.62	±0.08
127	1-7/16	1-5/8	3/32	1.424	±0.012	0.103	±0.003	36.17	±0.30	2.62	±0.08
128	1-1/2	1-11/16	3/32	1.487	±0.012	0.103	±0.003	37.77	±0.30	2.62	±0.08
129	1-9/16	1-3/4	3/32	1.549	±0.015	0.103	±0.003	39.34	±0.38	2.62	±0.08
130	1-5/8	1-13/16	3/32	1.612	±0.015	0.103	±0.003	40.94	±0.38	2.62	±0.08
131	1-11/16	1-7/8	3/32	1.674	±0.015	0.103	±0.003	42.52	±0.38	2.62	±0.08
132	1-3/4	1-15/16	3/32	1.737	±0.015	0.103	±0.003	44.12	±0.38	2.62	±0.08
133	1-13/16	2	3/32	1.799	±0.015	0.103	±0.003	45.69	±0.38	2.62	±0.08
134	1-7/8	2-1/16	3/32	1.862	±0.015	0.103	±0.003	47.29	±0.38	2.62	±0.08
135	1-15/16	2-1/8	3/32	1.925	±0.017	0.103	±0.003	48.90	±0.43	2.62	±0.08
136	2	2-3/16	3/32	1.987	±0.017	0.103	±0.003	50.47	±0.43	2.62	±0.08
137	2-1/16	2-1/4	3/32	2.050	±0.017	0.103	±0.003	52.07	±0.43	2.62	±0.08
138	2-1/8	2-5/16	3/32	2.112	±0.017	0.103	±0.003	53.64	±0.43	2.62	±0.08
139	2-3/16	2-3/8	3/32	2.175	±0.017	0.103	±0.003	55.25	±0.43	2.62	±0.08
140	2-1/4	2-7/16	3/32	2.237	±0.017	0.103	±0.003	56.82	±0.43	2.62	±0.08
141	2-5/16	2-1/2	3/32	2.300	±0.020	0.103	±0.003	58.42	±0.51	2.62	±0.08
142	2-3/8	2-9/16	3/32	2.362	±0.020	0.103	±0.003	59.99	±0.51	2.62	±0.08
143	2-7/16	2-5/8	3/32	2.425	±0.020	0.103	±0.003	61.60	±0.51	2.62	±0.08
144	2-1/2	2-11/16	3/32	2.487	±0.020	0.103	±0.003	63.17	±0.51	2.62	±0.08
145	2-9/16	2-3/4	3/32	2.550	±0.020	0.103	±0.003	64.77	±0.51	2.62	±0.08
146	2-5/8	2-13/16	3/32	2.612	±0.020	0.103	±0.003	66.34	±0.51	2.62	±0.08
147	2-11/16	2-7/8	3/32	2.675	±0.022	0.103	±0.003	67.95	±0.56	2.62	±0.08
148	2-3/4	2-15/16	3/32	2.737	±0.022	0.103	±0.003	69.52	±0.56	2.62	±0.08
149	2-13/16	3	3/32	2.800	±0.022	0.103	±0.003	71.12	±0.56	2.62	±0.08
150	2-7/8	3-1/16	3/32	2.862	±0.022	0.103	±0.003	72.69	±0.56	2.62	±0.08
151	3	3-3/16	3/32	2.987	±0.024	0.103	±0.003	75.87	±0.61	2.62	±0.08
152	3-1/4	3-7/16	3/32	3.237	±0.024	0.103	±0.003	82.22	±0.61	2.62	±0.08
153	3-1/2	3-11/16	3/32	3.487	±0.024	0.103	±0.003	88.57	±0.61	2.62	±0.08
154	3-3/4	3-15/16	3/32	3.737	±0.028	0.103	±0.003	94.92	±0.71	2.62	±0.08
155	4	4-3/16	3/32	3.987	±0.028	0.103	±0.003	101.27	±0.71	2.62	±0.08
156	4-1/4	4-7/16	3/32	4.237	±0.030	0.103	±0.003	107.62	±0.76	2.62	±0.08
157	4-1/2	4-11/16	3/32	4.487	±0.030	0.103	±0.003	113.97	±0.76	2.62	±0.08
158	4-3/4	4-15/16	3/32	4.737	±0.030	0.103	±0.003	120.32	±0.76	2.62	±0.08
159	5	5-3/16	3/32	4.987	±0.035	0.103	±0.003	126.67	±0.89	2.62	±0.08
160	5-1/4	5-7/16	3/32	5.237	±0.035	0.103	±0.003	133.02	±0.89	2.62	±0.08
161	5-1/2	5-11/16	3/32	5.487	±0.035	0.103	±0.003	139.37	±0.89	2.62	±0.08
162	5-3/4	5-15/16	3/32	5.737	±0.035	0.103	±0.003	145.72	±0.89	2.62	±0.08
163	6	6-3/16	3/32	5.987	±0.035	0.103	±0.003	152.07	±0.89	2.62	±0.08
164	6-1/4	6-7/16	3/32	6.237	±0.040	0.103	±0.003	158.42	±1.02	2.62	±0.08
165	6-1/2	6-11/16	3/32	6.487	±0.040	0.103	±0.003	164.77	±1.02	2.62	±0.08
166	6-3/4	6-15/16	3/32	6.737	±0.040	0.103	±0.003	171.12	±1.02	2.62	±0.08
167	7	7-3/16	3/32	6.987	±0.040	0.103	±0.003	177.47	±1.02	2.62	±0.08
168	7-1/4	7-7/16	3/32	7.237	±0.045	0.103	±0.003	183.82	±1.14	2.62	±0.08
169	7-1/2	7-11/16	3/32	7.487	±0.045	0.103	±0.003	190.17	±1.14	2.62	±0.08
170	7-3/4	7-15/16	3/32	7.737	±0.045	0.103	±0.003	196.52	±1.14	2.62	±0.08
171	8	8-3/16	3/32	7.987	±0.045	0.103	±0.003	202.87	±1.14	2.62	±0.08
172	8-1/4	8-7/16	3/32	8.237	±0.050	0.103	±0.003	209.22	±1.27	2.62	±0.08
173	8-1/2	8-11/16	3/32	8.487	±0.050	0.103	±0.003	215.57	±1.27	2.62	±0.08
174	8-3/4	8-15/16	3/32	8.737	±0.050	0.103	±0.003	221.92	±1.27	2.62	±0.08
175	9	9-3/16	3/32	8.987	±0.050	0.103	±0.003	228.27	±1.27	2.62	±0.08
176	9-1/4	9-7/16	3/32	9.237	±0.055	0.103	±0.003	234.62	±1.40	2.62	±0.08
177	9-1/2	9-11/16	3/32	9.487	±0.055	0.103	±0.003	240.97	±1.40	2.62	±0.08
178	9-3/4	9-15/16	3/32	9.737	±0.055	0.103	±0.003	247.32	±1.40	2.62	±0.08
200 SeriesC/S = 1/8" (0.139" / 3.53 mm)
201	3/16	7/16	1/8	0.171	±0.005	0.139	±0.004	4.34	±0.13	3.53	±0.10
202	1/4	1/2	1/8	0.234	±0.005	0.139	±0.004	5.94	±0.13	3.53	±0.10
203	5/16	9/16	1/8	0.296	±0.005	0.139	±0.004	7.52	±0.13	3.53	±0.10
204	3/8	5/8	1/8	0.359	±0.005	0.139	±0.004	9.12	±0.13	3.53	±0.10
205	7/16	11/16	1/8	0.421	±0.005	0.139	±0.004	10.69	±0.13	3.53	±0.10
206	1/2	3/4	1/8	0.484	±0.005	0.139	±0.004	12.29	±0.13	3.53	±0.10
207	9/16	13/16	1/8	0.546	±0.007	0.139	±0.004	13.87	±0.18	3.53	±0.10
208	5/8	7/8	1/8	0.609	±0.009	0.139	±0.004	15.47	±0.23	3.53	±0.10
209	11/16	15/16	1/8	0.671	±0.009	0.139	±0.004	17.04	±0.23	3.53	±0.10
210	3/4	1	1/8	0.734	±0.010	0.139	±0.004	18.64	±0.25	3.53	±0.10
211	13/16	1-1/16	1/8	0.796	±0.010	0.139	±0.004	20.22	±0.25	3.53	±0.10
212	7/8	1-1/8	1/8	0.859	±0.010	0.139	±0.004	21.82	±0.25	3.53	±0.10
213	15/16	1-3/16	1/8	0.921	±0.010	0.139	±0.004	23.39	±0.25	3.53	±0.10
214	1	1-1/4	1/8	0.984	±0.010	0.139	±0.004	24.99	±0.25	3.53	±0.10
215	1-1/16	1-5/16	1/8	1.046	±0.010	0.139	±0.004	26.57	±0.25	3.53	±0.10
216	1-1/8	1-3/8	1/8	1.109	±0.012	0.139	±0.004	28.17	±0.30	3.53	±0.10
217	1-3/16	1-7/16	1/8	1.171	±0.012	0.139	±0.004	29.74	±0.30	3.53	±0.10
218	1-1/4	1-1/2	1/8	1.234	±0.012	0.139	±0.004	31.34	±0.30	3.53	±0.10
219	1-5/16	1-9/16	1/8	1.296	±0.012	0.139	±0.004	32.92	±0.30	3.53	±0.10
220	1-3/8	1-5/8	1/8	1.359	±0.012	0.139	±0.004	34.52	±0.30	3.53	±0.10
221	1-7/16	1-11/16	1/8	1.421	±0.012	0.139	±0.004	36.09	±0.30	3.53	±0.10
222	1-1/2	1-3/4	1/8	1.484	±0.015	0.139	±0.004	37.69	±0.38	3.53	±0.10
223	1-5/8	1-7/8	1/8	1.609	±0.015	0.139	±0.004	40.87	±0.38	3.53	±0.10
224	1-3/4	2	1/8	1.734	±0.015	0.139	±0.004	44.04	±0.38	3.53	±0.10
225	1-7/8	2-1/8	1/8	1.859	±0.018	0.139	±0.004	47.22	±0.46	3.53	±0.10
226	2	2-1/4	1/8	1.984	±0.018	0.139	±0.004	50.39	±0.46	3.53	±0.10
227	2-1/8	2-3/8	1/8	2.109	±0.018	0.139	±0.004	53.57	±0.46	3.53	±0.10
228	2-1/4	2-1/2	1/8	2.234	±0.020	0.139	±0.004	56.74	±0.51	3.53	±0.10
229	2-3/8	2-5/8	1/8	2.359	±0.020	0.139	±0.004	59.92	±0.51	3.53	±0.10
230	2-1/2	2-3/4	1/8	2.484	±0.020	0.139	±0.004	63.09	±0.51	3.53	±0.10
231	2-5/8	2-7/8	1/8	2.609	±0.020	0.139	±0.004	66.27	±0.51	3.53	±0.10
232	2-3/4	3	1/8	2.734	±0.024	0.139	±0.004	69.44	±0.61	3.53	±0.10
233	2-7/8	3-1/8	1/8	2.859	±0.024	0.139	±0.004	72.62	±0.61	3.53	±0.10
234	3	3-1/4	1/8	2.984	±0.024	0.139	±0.004	75.79	±0.61	3.53	±0.10
235	3-1/8	3-3/8	1/8	3.109	±0.024	0.139	±0.004	78.97	±0.61	3.53	±0.10
236	3-1/4	3-1/2	1/8	3.234	±0.024	0.139	±0.004	82.14	±0.61	3.53	±0.10
237	3-3/8	3-5/8	1/8	3.359	±0.024	0.139	±0.004	85.32	±0.61	3.53	±0.10
238	3-1/2	3-3/4	1/8	3.484	±0.024	0.139	±0.004	88.49	±0.61	3.53	±0.10
239	3-5/8	3-7/8	1/8	3.609	±0.028	0.139	±0.004	91.67	±0.71	3.53	±0.10
240	3-3/4	4	1/8	3.734	±0.028	0.139	±0.004	94.84	±0.71	3.53	±0.10
241	3-7/8	4-1/8	1/8	3.859	±0.028	0.139	±0.004	98.02	±0.71	3.53	±0.10
242	4	4-1/4	1/8	3.984	±0.028	0.139	±0.004	101.19	±0.71	3.53	±0.10
243	4-1/8	4-3/8	1/8	4.109	±0.028	0.139	±0.004	104.37	±0.71	3.53	±0.10
244	4-1/4	4-1/2	1/8	4.234	±0.030	0.139	±0.004	107.54	±0.76	3.53	±0.10
245	4-3/8	4-5/8	1/8	4.359	±0.030	0.139	±0.004	110.72	±0.76	3.53	±0.10
246	4-1/2	4-3/4	1/8	4.484	±0.030	0.139	±0.004	113.89	±0.76	3.53	±0.10
247	4-5/8	4-7/8	1/8	4.609	±0.030	0.139	±0.004	117.07	±0.76	3.53	±0.10
248	4-3/4	5	1/8	4.734	±0.030	0.139	±0.004	120.24	±0.76	3.53	±0.10
249	4-7/8	5-1/8	1/8	4.859	±0.035	0.139	±0.004	123.42	±0.89	3.53	±0.10
250	5	5-1/4	1/8	4.984	±0.035	0.139	±0.004	126.59	±0.89	3.53	±0.10
251	5-1/8	5-3/8	1/8	5.109	±0.035	0.139	±0.004	129.77	±0.89	3.53	±0.10
252	5-1/4	5-1/2	1/8	5.234	±0.035	0.139	±0.004	132.94	±0.89	3.53	±0.10
253	5-3/8	5-5/8	1/8	5.359	±0.035	0.139	±0.004	136.12	±0.89	3.53	±0.10
254	5-1/2	5-3/4	1/8	5.484	±0.035	0.139	±0.004	139.29	±0.89	3.53	±0.10
255	5-5/8	5-7/8	1/8	5.609	±0.035	0.139	±0.004	142.47	±0.89	3.53	±0.10
256	5-3/4	6	1/8	5.734	±0.035	0.139	±0.004	145.64	±0.89	3.53	±0.10
258	6	6-1/4	1/8	5.984	±0.035	0.139	±0.004	151.99	±0.89	3.53	±0.10
259	6-1/4	6-1/2	1/8	6.234	±0.040	0.139	±0.004	158.34	±1.02	3.53	±0.10
260	6-1/2	6-3/4	1/8	6.484	±0.040	0.139	±0.004	164.69	±1.02	3.53	±0.10
261	6-3/4	7	1/8	6.734	±0.040	0.139	±0.004	171.04	±1.02	3.53	±0.10
262	7	7-1/4	1/8	6.984	±0.040	0.139	±0.004	177.39	±1.02	3.53	±0.10
263	7-1/4	7-1/2	1/8	7.234	±0.045	0.139	±0.004	183.74	±1.14	3.53	±0.10
264	7-1/2	7-3/4	1/8	7.484	±0.045	0.139	±0.004	190.09	±1.14	3.53	±0.10
265	7-3/4	8	1/8	7.734	±0.045	0.139	±0.004	196.44	±1.14	3.53	±0.10
266	8	8-1/4	1/8	7.984	±0.045	0.139	±0.004	202.79	±1.14	3.53	±0.10
267	8-1/4	8-1/2	1/8	8.234	±0.050	0.139	±0.004	209.14	±1.27	3.53	±0.10
268	8-1/2	8-3/4	1/8	8.484	±0.050	0.139	±0.004	215.49	±1.27	3.53	±0.10
269	8-3/4	9	1/8	8.734	±0.050	0.139	±0.004	221.84	±1.27	3.53	±0.10
270	9	9-1/4	1/8	8.984	±0.050	0.139	±0.004	228.19	±1.27	3.53	±0.10
271	9-1/4	9-1/2	1/8	9.234	±0.055	0.139	±0.004	234.54	±1.40	3.53	±0.10
272	9-1/2	9-3/4	1/8	9.484	±0.055	0.139	±0.004	240.89	±1.40	3.53	±0.10
273	9-3/4	10	1/8	9.734	±0.055	0.139	±0.004	247.24	±1.40	3.53	±0.10
274	10	10-1/4	1/8	9.984	±0.055	0.139	±0.004	253.59	±1.40	3.53	±0.10
275	10-1/2	10-3/4	1/8	10.484	±0.055	0.139	±0.004	266.29	±1.40	3.53	±0.10
276	11	11-1/4	1/8	10.984	±0.065	0.139	±0.004	278.99	±1.65	3.53	±0.10
277	11-1/2	11-3/4	1/8	11.484	±0.065	0.139	±0.004	291.69	±1.65	3.53	±0.10
278	12	12-1/4	1/8	11.984	±0.065	0.139	±0.004	304.39	±1.65	3.53	±0.10
279	13	13-1/4	1/8	12.984	±0.065	0.139	±0.004	329.79	±1.65	3.53	±0.10
280	14	14-1/4	1/8	13.984	±0.065	0.139	±0.004	355.19	±1.65	3.53	±0.10
281	15	15-1/4	1/8	14.984	±0.065	0.139	±0.004	380.59	±1.65	3.53	±0.10
282	16	16-1/4	1/8	15.955	±0.075	0.139	±0.004	405.26	±1.91	3.53	±0.10
283	17	17-1/4	1/8	16.956	±0.080	0.139	±0.004	430.68	±2.03	3.53	±0.10
284	18	18-1/4	1/8	17.955	±0.085	0.139	±0.004	456.06	±2.16	3.53	±0.10
300 SeriesC/S = 3/16" (0.210" / 5.33 mm)
309	7/16	13/16	3/16	0.412	±0.005	0.210	±0.005	10.46	±0.13	5.33	±0.13
310	1/2	7/8	3/16	0.475	±0.005	0.210	±0.005	12.07	±0.13	5.33	±0.13
311	9/16	15/16	3/16	0.537	±0.007	0.210	±0.005	13.64	±0.18	5.33	±0.13
312	5/8	1	3/16	0.600	±0.009	0.210	±0.005	15.24	±0.23	5.33	±0.13
313	11/16	1-1/16	3/16	0.662	±0.009	0.210	±0.005	16.81	±0.23	5.33	±0.13
314	3/4	1-1/8	3/16	0.725	±0.010	0.210	±0.005	18.42	±0.25	5.33	±0.13
315	13/16	1-3/16	3/16	0.787	±0.010	0.210	±0.005	19.99	±0.25	5.33	±0.13
316	7/8	1-1/4	3/16	0.850	±0.010	0.210	±0.005	21.59	±0.25	5.33	±0.13
317	15/16	1-5/16	3/16	0.912	±0.010	0.210	±0.005	23.16	±0.25	5.33	±0.13
318	1	1-3/8	3/16	0.975	±0.010	0.210	±0.005	24.77	±0.25	5.33	±0.13
319	1-1/16	1-7/16	3/16	1.037	±0.010	0.210	±0.005	26.34	±0.25	5.33	±0.13
320	1-1/8	1-1/2	3/16	1.100	±0.012	0.210	±0.005	27.94	±0.30	5.33	±0.13
321	1-3/16	1-9/16	3/16	1.162	±0.012	0.210	±0.005	29.51	±0.30	5.33	±0.13
322	1-1/4	1-5/8	3/16	1.225	±0.012	0.210	±0.005	31.12	±0.30	5.33	±0.13
323	1-5/16	1-11/16	3/16	1.287	±0.012	0.210	±0.005	32.69	±0.30	5.33	±0.13
324	1-3/8	1-3/4	3/16	1.350	±0.012	0.210	±0.005	34.29	±0.30	5.33	±0.13
325	1-1/2	1-7/8	3/16	1.475	±0.015	0.210	±0.005	37.47	±0.38	5.33	±0.13
326	1-5/8	2	3/16	1.600	±0.015	0.210	±0.005	40.64	±0.38	5.33	±0.13
327	1-3/4	2-1/8	3/16	1.725	±0.015	0.210	±0.005	43.82	±0.38	5.33	±0.13
328	1-7/8	2-1/4	3/16	1.850	±0.015	0.210	±0.005	46.99	±0.38	5.33	±0.13
329	2	2-3/8	3/16	1.975	±0.018	0.210	±0.005	50.17	±0.46	5.33	±0.13
330	2-1/8	2-1/2	3/16	2.100	±0.018	0.210	±0.005	53.34	±0.46	5.33	±0.13
331	2-1/4	2-5/8	3/16	2.225	±0.018	0.210	±0.005	56.52	±0.46	5.33	±0.13
332	2-3/8	2-3/4	3/16	2.350	±0.018	0.210	±0.005	59.69	±0.46	5.33	±0.13
333	2-1/2	2-7/8	3/16	2.475	±0.020	0.210	±0.005	62.87	±0.51	5.33	±0.13
334	2-5/8	3	3/16	2.600	±0.020	0.210	±0.005	66.04	±0.51	5.33	±0.13
335	2-3/4	3-1/8	3/16	2.725	±0.020	0.210	±0.005	69.22	±0.51	5.33	±0.13
336	2-7/8	3-1/4	3/16	2.850	±0.020	0.210	±0.005	72.39	±0.51	5.33	±0.13
337	3	3-3/8	3/16	2.975	±0.024	0.210	±0.005	75.57	±0.61	5.33	±0.13
338	3-1/8	3-1/2	3/16	3.100	±0.024	0.210	±0.005	78.74	±0.61	5.33	±0.13
339	3-1/4	3-5/8	3/16	3.225	±0.024	0.210	±0.005	81.92	±0.61	5.33	±0.13
340	3-3/8	3-3/4	3/16	3.350	±0.024	0.210	±0.005	85.09	±0.61	5.33	±0.13
341	3-1/2	3-7/8	3/16	3.475	±0.024	0.210	±0.005	88.27	±0.61	5.33	±0.13
342	3-5/8	4	3/16	3.600	±0.028	0.210	±0.005	91.44	±0.71	5.33	±0.13
343	3-3/4	4-1/8	3/16	3.725	±0.028	0.210	±0.005	94.62	±0.71	5.33	±0.13
344	3-7/8	4-1/4	3/16	3.850	±0.028	0.210	±0.005	97.79	±0.71	5.33	±0.13
345	4	4-3/8	3/16	3.975	±0.028	0.210	±0.005	100.97	±0.71	5.33	±0.13
346	4-1/8	4-1/2	3/16	4.100	±0.028	0.210	±0.005	104.14	±0.71	5.33	±0.13
347	4-1/4	4-5/8	3/16	4.225	±0.030	0.210	±0.005	107.32	±0.76	5.33	±0.13
348	4-3/8	4-3/4	3/16	4.350	±0.030	0.210	±0.005	110.49	±0.76	5.33	±0.13
349	4-1/2	4-7/8	3/16	4.475	±0.030	0.210	±0.005	113.67	±0.76	5.33	±0.13
350	4-5/8	5	3/16	4.600	±0.030	0.210	±0.005	116.84	±0.76	5.33	±0.13
351	4-3/4	5-1/8	3/16	4.725	±0.030	0.210	±0.005	120.02	±0.76	5.33	±0.13
352	4-7/8	5-1/4	3/16	4.850	±0.030	0.210	±0.005	123.19	±0.76	5.33	±0.13
353	5	5-3/8	3/16	4.975	±0.037	0.210	±0.005	126.37	±0.94	5.33	±0.13
354	5-1/8	5-1/2	3/16	5.100	±0.037	0.210	±0.005	129.54	±0.94	5.33	±0.13
355	5-1/4	5-5/8	3/16	5.225	±0.037	0.210	±0.005	132.72	±0.94	5.33	±0.13
356	5-3/8	5-3/4	3/16	5.350	±0.037	0.210	±0.005	135.89	±0.94	5.33	±0.13
357	5-1/2	5-7/8	3/16	5.475	±0.037	0.210	±0.005	139.07	±0.94	5.33	±0.13
358	5-5/8	6	3/16	5.600	±0.037	0.210	±0.005	142.24	±0.94	5.33	±0.13
359	5-3/4	6-1/8	3/16	5.725	±0.037	0.210	±0.005	145.42	±0.94	5.33	±0.13
360	5-7/8	6-1/4	3/16	5.850	±0.037	0.210	±0.005	148.59	±0.94	5.33	±0.13
361	6	6-3/8	3/16	5.975	±0.037	0.210	±0.005	151.77	±0.94	5.33	±0.13
362	6-1/4	6-5/8	3/16	6.225	±0.040	0.210	±0.005	158.12	±1.02	5.33	±0.13
363	6-1/2	6-7/8	3/16	6.475	±0.040	0.210	±0.005	164.47	±1.02	5.33	±0.13
364	6-3/4	7-1/8	3/16	6.725	±0.040	0.210	±0.005	170.82	±1.02	5.33	±0.13
365	7	7-3/8	3/16	6.975	±0.040	0.210	±0.005	177.17	±1.02	5.33	±0.13
366	7-1/4	7-5/8	3/16	7.225	±0.045	0.210	±0.005	183.52	±1.14	5.33	±0.13
367	7-1/2	7-7/8	3/16	7.475	±0.045	0.210	±0.005	189.87	±1.14	5.33	±0.13
368	7-3/4	8-1/8	3/16	7.725	±0.045	0.210	±0.005	196.22	±1.14	5.33	±0.13
369	8	8-3/8	3/16	7.975	±0.045	0.210	±0.005	202.57	±1.14	5.33	±0.13
370	8-1/4	8-5/8	3/16	8.225	±0.050	0.210	±0.005	208.92	±1.27	5.33	±0.13
371	8-1/2	8-7/8	3/16	8.475	±0.050	0.210	±0.005	215.27	±1.27	5.33	±0.13
372	8-3/4	9-1/8	3/16	8.725	±0.050	0.210	±0.005	221.62	±1.27	5.33	±0.13
373	9	9-3/8	3/16	8.975	±0.050	0.210	±0.005	227.97	±1.27	5.33	±0.13
374	9-1/4	9-5/8	3/16	9.225	±0.055	0.210	±0.005	234.32	±1.40	5.33	±0.13
375	9-1/2	9-7/8	3/16	9.475	±0.055	0.210	±0.005	240.67	±1.40	5.33	±0.13
376	9-3/4	10-1/8	3/16	9.725	±0.055	0.210	±0.005	247.02	±1.40	5.33	±0.13
377	10	10-3/8	3/16	9.975	±0.055	0.210	±0.005	253.37	±1.52	5.33	±0.13
378	10-1/2	10-7/8	3/16	10.475	±0.060	0.210	±0.005	266.07	±1.52	5.33	±0.13
379	11	11-3/8	3/16	10.975	±0.060	0.210	±0.005	278.77	±1.52	5.33	±0.13
380	11-1/2	11-7/8	3/16	11.475	±0.065	0.210	±0.005	291.47	±1.65	5.33	±0.13
381	12	12-3/8	3/16	11.975	±0.065	0.210	±0.005	304.17	±1.65	5.33	±0.13
382	13	13-3/8	3/16	12.975	±0.065	0.210	±0.005	329.57	±1.65	5.33	±0.13
383	14	14-3/8	3/16	13.975	±0.070	0.210	±0.005	354.97	±1.78	5.33	±0.13
384	15	15-3/8	3/16	14.975	±0.070	0.210	±0.005	380.37	±1.78	5.33	±0.13
385	16	16-3/8	3/16	15.955	±0.075	0.210	±0.005	405.26	±1.91	5.33	±0.13
386	17	17-3/8	3/16	16.955	±0.080	0.210	±0.005	430.66	±2.03	5.33	±0.13
387	18	18-3/8	3/16	17.955	±0.085	0.210	±0.005	456.06	±2.16	5.33	±0.13
388	19	19-3/8	3/16	18.952	±0.090	0.210	±0.005	481.38	±2.29	5.33	±0.13
389	20	20-3/8	3/16	19.952	±0.095	0.210	±0.005	506.78	±2.41	5.33	±0.13
390	21	21-3/8	3/16	20.952	±0.095	0.210	±0.005	532.18	±2.41	5.33	±0.13
391	22	22-3/8	3/16	21.952	±0.100	0.210	±0.005	557.58	±2.54	5.33	±0.13
392	23	23-3/8	3/16	22.940	±0.105	0.210	±0.005	582.68	±2.67	5.33	±0.13
393	24	24-3/8	3/16	23.940	±0.110	0.210	±0.005	608.08	±2.79	5.33	±0.13
394	25	25-3/8	3/16	24.940	±0.115	0.210	±0.005	633.48	±2.92	5.33	±0.13
395	26	26-3/8	3/16	25.940	±0.120	0.210	±0.005	658.88	±3.05	5.33	±0.13
400 SeriesC/S = 1/4" (0.275" / 6.99 mm)
425	4-1/2	5	1/4	4.475	±0.033	0.275	±0.006	113.67	±0.84	6.99	±0.15
426	4-5/8	5-1/8	1/4	4.600	±0.033	0.275	±0.006	116.84	±0.84	6.99	±0.15
427	4-3/4	5-1/4	1/4	4.725	±0.033	0.275	±0.006	120.02	±0.84	6.99	±0.15
428	4-7/8	5-3/8	1/4	4.850	±0.033	0.275	±0.006	123.19	±0.84	6.99	±0.15
429	5	5-1/2	1/4	4.975	±0.037	0.275	±0.006	126.37	±0.94	6.99	±0.15
430	5-1/8	5-5/8	1/4	5.100	±0.037	0.275	±0.006	129.54	±0.94	6.99	±0.15
431	5-1/4	5-3/4	1/4	5.225	±0.037	0.275	±0.006	132.72	±0.94	6.99	±0.15
432	5-3/8	5-7/8	1/4	5.350	±0.037	0.275	±0.006	135.89	±0.94	6.99	±0.15
433	5-1/2	6	1/4	5.475	±0.037	0.275	±0.006	139.07	±0.94	6.99	±0.15
434	5-5/8	6-1/8	1/4	5.600	±0.037	0.275	±0.006	142.24	±0.94	6.99	±0.15
435	5-3/4	6-1/4	1/4	5.725	±0.037	0.275	±0.006	145.42	±0.94	6.99	±0.15
436	5-7/8	6-3/8	1/4	5.850	±0.037	0.275	±0.006	148.59	±0.94	6.99	±0.15
437	6	6-1/2	1/4	5.975	±0.037	0.275	±0.006	151.77	±0.94	6.99	±0.15
438	6-1/4	6-3/4	1/4	6.225	±0.040	0.275	±0.006	158.12	±1.02	6.99	±0.15
439	6-1/2	7	1/4	6.475	±0.040	0.275	±0.006	164.47	±1.02	6.99	±0.15
440	6-3/4	7-1/4	1/4	6.725	±0.040	0.275	±0.006	170.82	±1.02	6.99	±0.15
441	7	7-1/2	1/4	6.975	±0.040	0.275	±0.006	177.17	±1.02	6.99	±0.15
442	7-1/4	7-3/4	1/4	7.225	±0.045	0.275	±0.006	183.52	±1.14	6.99	±0.15
443	7-1/2	8	1/4	7.475	±0.045	0.275	±0.006	189.87	±1.14	6.99	±0.15
444	7-3/4	8-1/4	1/4	7.725	±0.045	0.275	±0.006	196.22	±1.14	6.99	±0.15
445	8	8-1/2	1/4	7.975	±0.045	0.275	±0.006	202.57	±1.14	6.99	±0.15
446	8-1/2	9	1/4	8.475	±0.055	0.275	±0.006	215.27	±1.40	6.99	±0.15
447	9	9-1/2	1/4	8.975	±0.055	0.275	±0.006	227.97	±1.40	6.99	±0.15
448	9-1/2	10	1/4	9.475	±0.055	0.275	±0.006	240.67	±1.40	6.99	±0.15
449	10	10-1/2	1/4	9.975	±0.055	0.275	±0.006	253.37	±1.40	6.99	±0.15
450	10-1/2	11	1/4	10.475	±0.060	0.275	±0.006	266.07	±1.52	6.99	±0.15
451	11	11-1/2	1/4	10.975	±0.060	0.275	±0.006	278.77	±1.52	6.99	±0.15
452	11-1/2	12	1/4	11.475	±0.060	0.275	±0.006	291.47	±1.52	6.99	±0.15
453	12	12-1/2	1/4	11.975	±0.060	0.275	±0.006	304.17	±1.52	6.99	±0.15
454	12-1/2	13	1/4	12.475	±0.060	0.275	±0.006	316.87	±1.52	6.99	±0.15
455	13	13-1/2	1/4	12.975	±0.060	0.275	±0.006	329.57	±1.52	6.99	±0.15
456	13-1/2	14	1/4	13.475	±0.070	0.275	±0.006	342.27	±1.78	6.99	±0.15
457	14	14-1/2	1/4	13.975	±0.070	0.275	±0.006	345.97	±1.78	6.99	±0.15
458	14-1/2	15	1/4	14.475	±0.070	0.275	±0.006	367.67	±1.78	6.99	±0.15
459	15	15-1/2	1/4	14.975	±0.070	0.275	±0.006	380.37	±1.78	6.99	±0.15
460	15-1/2	16	1/4	15.475	±0.070	0.275	±0.006	393.07	±1.78	6.99	±0.15
461	16	16-1/2	1/4	15.955	±0.075	0.275	±0.006	405.26	±1.91	6.99	±0.15
462	16-1/2	17	1/4	16.455	±0.075	0.275	±0.006	417.96	±1.91	6.99	±0.15
463	17	17-1/2	1/4	16.955	±0.080	0.275	±0.006	430.66	±2.03	6.99	±0.15
464	17-1/2	18	1/4	17.455	±0.085	0.275	±0.006	443.36	±2.16	6.99	±0.15
465	18	18-1/2	1/4	17.955	±0.085	0.275	±0.006	456.06	±2.16	6.99	±0.15
466	18-1/2	19	1/4	18.455	±0.085	0.275	±0.006	468.76	±2.16	6.99	±0.15
467	19	19-1/2	1/4	18.955	±0.090	0.275	±0.006	481.46	±2.29	6.99	±0.15
468	19-1/2	20	1/4	19.455	±0.090	0.275	±0.006	494.16	±2.29	6.99	±0.15
469	20	20-1/2	1/4	19.955	±0.095	0.275	±0.006	506.86	±2.41	6.99	±0.15
470	21	21-1/2	1/4	20.955	±0.095	0.275	±0.006	532.26	±2.41	6.99	±0.15
471	22	22-1/2	1/4	21.955	±0.100	0.275	±0.006	557.66	±2.54	6.99	±0.15
472	23	23-1/2	1/4	22.940	±0.105	0.275	±0.006	582.68	±2.67	6.99	±0.15
473	24	24-1/2	1/4	23.940	±0.110	0.275	±0.006	608.08	±2.79	6.99	±0.15
474	25	25-1/2	1/4	24.940	±0.115	0.275	±0.006	633.48	±2.92	6.99	±0.15
475	26	26-1/2	1/4	25.940	±0.120	0.275	±0.006	658.88	±3.05	6.99	±0.15

Frequently Asked Questions

What is an AS568 O-ring size chart?

AS568 is the Aerospace Standard published by SAE International that defines the standard dimensions and tolerances for O-rings used in North America. The AS568 size chart lists an extensive range of dash sizes and is one of the most widely referenced O-ring standards in industrial and hydraulic applications.

How do I measure an O-ring?

O-rings are defined by two primary dimensions: inner diameter (I.D.) and cross-section (C/S). Accurate measurement is typically performed using a caliper. The outer diameter (O.D.) is derived using: O.D. = I.D. + (2 × C/S). Measured values can then be matched to the corresponding dash number in the chart.

What's the difference between imperial and metric O-ring sizes?

Imperial O-ring sizes follow the AS568 standard and are measured in inches. Metric O-rings follow standards such as ISO 3601 and are measured in millimetres. This chart provides both imperial and metric values to support cross-referencing between standards.

What materials are O-rings available in?

O-rings are manufactured in a variety of elastomers depending on the application, including Nitrile (Buna-N), Viton® (FKM), EPDM, Silicone, Neoprene, PTFE, and more. Material selection depends on factors like temperature range, chemical compatibility, and pressure. Check our Material Summary Guide for more information or contact our team of sealing specialists for material recommendations.

Frequently Asked Questions

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