AS 568 A O-ring standard specifications (inch)

I learned much of this information from the Frederick Seal, American Seal and Packing, and Precision Associates websites.

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About the AS 568 A standard for O-rings

The AS 568 A standard for O-rings is produced by the Society of Automotive Engineers AS (Aerospace Standard). The AS 568 A specification describes 369 O-rings. Each size is designated with a dash number and can be described using two values: the inside diameter and diameter of the cross-section. Except for the -9## O-rings, all American inch O-rings can be categorized into seven cross-sections and 119 inside diameters.

The nominal size for any given American inch o-ring, however, is different than the actual physical dimension of the o-ring. As an example, consider the -001 o-ring. Nominally, it is described as having a cross-section of ¹⁄₃₂ inch. The decimal equivalent of ¹⁄₃₂ inch is 0.03125 inch. However, the actual cross-section is 0.04 inch. Why the discrepancy? The nominal sizing of the American inch system is meant to describe the size of the groove in which the O-ring resides. Since all O-rings must be squeezed by about 10% to 15% in order to seal properly, the extra size of the O-ring handles the needed squeeze.

O-rings with a nominal cross-section of ¹⁄₃₂ inch (-001)

Size reference code (dash number)	Nominal size in inches			Decimal size in inches		Decimal size in millimeters
Size reference code (dash number)	ID	OD	Cross-section	ID	Cross-section	ID	Cross-section
-001	¹⁄₃₂	³⁄₃₂	¹⁄₃₂	.029 ± 0.004	.040 ± 0.003	0.74 ± 0.10	1.02 ± 0.08

O-rings with a nominal cross-section of ³⁄₆₄ inch (-002)

Size reference code (dash number)	Nominal size in inches			Decimal size in inches		Decimal size in millimeters
Size reference code (dash number)	ID	OD	Cross-section	ID	Cross-section	ID	Cross-section
-002	³⁄₆₄	⁹⁄₆₄	³⁄₆₄	.042 ± 0.004	.050 ± 0.003	1.07 ± 0.10	1.27 ± 0.08

O-rings with a nominal cross-section of ¹⁄₁₆ inch (-0##)

Size reference code (dash number)	Nominal size in inches			Decimal size in inches		Decimal size in millimeters
Size reference code (dash number)	ID	OD	Cross-section	ID	Cross-section	ID	Cross-section
-003	¹⁄₁₆	³⁄₁₆	¹⁄₁₆	.056 ± 0.004	.060 ± 0.003	1.42 ± 0.10	1.52 ± 0.08
-004	⁵⁄₆₄	¹³⁄₆₄	¹⁄₁₆	.070 ± 0.005	.070 ± 0.003	1.78 ± 0.13	1.78 ± 0.08
-005	³⁄₃₂	⁷⁄₃₂	¹⁄₁₆	.101 ± 0.005	.070 ± 0.003	2.57 ± 0.13	1.78 ± 0.08
-006	¹⁄₈	¹⁄₄	¹⁄₁₆	.114 ± 0.005	.070 ± 0.003	2.90 ± 0.13	1.78 ± 0.08
-007	⁵⁄₃₂	⁹⁄₃₂	¹⁄₁₆	.145 ± 0.005	.070 ± 0.003	3.68 ± 0.13	1.78 ± 0.08
-008	³⁄₁₆	⁵⁄₁₆	¹⁄₁₆	.176 ± 0.005	.070 ± 0.003	4.47 ± 0.13	1.78 ± 0.08
-009	⁷⁄₃₂	¹¹⁄₃₂	¹⁄₁₆	.208 ± 0.005	.070 ± 0.003	5.28 ± 0.13	1.78 ± 0.08
-010	¹⁄₄	³⁄₈	¹⁄₁₆	.239 ± 0.005	.070 ± 0.003	6.07 ± 0.13	1.78 ± 0.08
-011	⁵⁄₁₆	⁷⁄₁₆	¹⁄₁₆	.301 ± 0.005	.070 ± 0.003	7.65 ± 0.13	1.78 ± 0.08
-012	³⁄₈	¹⁄₂	¹⁄₁₆	.364 ± 0.005	.070 ± 0.003	9.25 ± 0.13	1.78 ± 0.08
-013	⁷⁄₁₆	⁹⁄₁₆	¹⁄₁₆	.426 ± 0.005	.070 ± 0.003	10.82 ± 0.13	1.78 ± 0.08
-014	¹⁄₂	⁵⁄₈	¹⁄₁₆	.489 ± 0.005	.070 ± 0.003	12.42 ± 0.13	1.78 ± 0.08
-015	⁹⁄₁₆	¹¹⁄₁₆	¹⁄₁₆	.551 ± 0.007	.070 ± 0.003	14.00 ± 0.18	1.78 ± 0.08
-016	⁵⁄₈	³⁄₄	¹⁄₁₆	.614 ± 0.009	.070 ± 0.003	15.60 ± 0.23	1.78 ± 0.08
-017	¹¹⁄₁₆	¹³⁄₁₆	¹⁄₁₆	.676 ± 0.009	.070 ± 0.003	17.17 ± 0.23	1.78 ± 0.08
-018	³⁄₄	⁷⁄₈	¹⁄₁₆	.739 ± 0.009	.070 ± 0.003	18.77 ± 0.23	1.78 ± 0.08
-019	¹³⁄₁₆	¹⁵⁄₁₆	¹⁄₁₆	.801 ± 0.009	.070 ± 0.003	20.35 ± 0.23	1.78 ± 0.08
-020	⁷⁄₈	1	¹⁄₁₆	.864 ± 0.009	.070 ± 0.003	21.95 ± 0.23	1.78 ± 0.08
-021	¹⁵⁄₁₆	1 ¹⁄₁₆	¹⁄₁₆	.926 ± 0.009	.070 ± 0.003	23.52 ± 0.23	1.78 ± 0.08
-022	1	1 ¹⁄₈	¹⁄₁₆	.989 ± 0.010	.070 ± 0.003	25.12 ± 0.25	1.78 ± 0.08
-023	1 ¹⁄₁₆	1 ³⁄₁₆	¹⁄₁₆	1.051 ± 0.010	.070 ± 0.003	26.70 ± 0.25	1.78 ± 0.08
-024	1 ¹⁄₈	1 ¹⁄₄	¹⁄₁₆	1.114 ± 0.010	.070 ± 0.003	28.30 ± 0.25	1.78 ± 0.08
-025	1 ³⁄₁₆	1 ⁵⁄₁₆	¹⁄₁₆	1.176 ± 0.011	.070 ± 0.003	29.87 ± 0.28	1.78 ± 0.08
-026	1 ¹⁄₄	1 ³⁄₈	¹⁄₁₆	1.239 ± 0.011	.070 ± 0.003	31.47 ± 0.28	1.78 ± 0.08
-027	1 ⁵⁄₁₆	1 ⁷⁄₁₆	¹⁄₁₆	1.301 ± 0.011	.070 ± 0.003	33.05 ± 0.28	1.78 ± 0.08
-028	1 ³⁄₈	1 ¹⁄₂	¹⁄₁₆	1.364 ± 0.013	.070 ± 0.003	34.65 ± 0.33	1.78 ± 0.08
-029	1 ¹⁄₂	1 ⁵⁄₈	¹⁄₁₆	1.489 ± 0.013	.070 ± 0.003	37.82 ± 0.33	1.78 ± 0.08
-030	1 ⁵⁄₈	1 ³⁄₄	¹⁄₁₆	1.614 ± 0.013	.070 ± 0.003	41.00 ± 0.33	1.78 ± 0.08
-031	1 ³⁄₄	1 ⁷⁄₈	¹⁄₁₆	1.739 ± 0.015	.070 ± 0.003	44.17 ± 0.38	1.78 ± 0.08
-032	1 ⁷⁄₈	2	¹⁄₁₆	1.864 ± 0.015	.070 ± 0.003	47.35 ± 0.38	1.78 ± 0.08
-033	2	2 ¹⁄₈	¹⁄₁₆	1.989 ± 0.018	.070 ± 0.003	50.52 ± 0.46	1.78 ± 0.08
-034	2 ¹⁄₈	2 ¹⁄₄	¹⁄₁₆	2.114 ± 0.018	.070 ± 0.003	53.70 ± 0.46	1.78 ± 0.08
-035	2 ¹⁄₄	2 ³⁄₈	¹⁄₁₆	2.239 ± 0.018	.070 ± 0.003	56.87 ± 0.46	1.78 ± 0.08
-036	2 ³⁄₈	2 ¹⁄₂	¹⁄₁₆	2.364 ± 0.018	.070 ± 0.003	60.05 ± 0.46	1.78 ± 0.08
-037	2 ¹⁄₂	2 ⁵⁄₈	¹⁄₁₆	2.489 ± 0.018	.070 ± 0.003	63.22 ± 0.46	1.78 ± 0.08
-038	2 ⁵⁄₈	2 ³⁄₄	¹⁄₁₆	2.614 ± 0.020	.070 ± 0.003	66.40 ± 0.51	1.78 ± 0.08
-039	2 ³⁄₄	2 ⁷⁄₈	¹⁄₁₆	2.739 ± 0.020	.070 ± 0.003	69.57 ± 0.51	1.78 ± 0.08
-040	2 ⁷⁄₈	3	¹⁄₁₆	2.864 ± 0.020	.070 ± 0.003	72.75 ± 0.51	1.78 ± 0.08
-041	3	3 ¹⁄₈	¹⁄₁₆	2.989 ± 0.024	.070 ± 0.003	75.92 ± 0.61	1.78 ± 0.08
-042	3 ¹⁄₄	3 ³⁄₈	¹⁄₁₆	3.239 ± 0.024	.070 ± 0.003	82.27 ± 0.61	1.78 ± 0.08
-043	3 ¹⁄₂	3 ⁵⁄₈	¹⁄₁₆	3.489 ± 0.024	.070 ± 0.003	88.62 ± 0.61	1.78 ± 0.08
-044	3 ³⁄₄	3 ⁷⁄₈	¹⁄₁₆	3.739 ± 0.027	.070 ± 0.003	94.97 ± 0.69	1.78 ± 0.08
-045	4	4 ¹⁄₈	¹⁄₁₆	3.989 ± 0.027	.070 ± 0.003	101.32 ± 0.69	1.78 ± 0.08
-046	4 ¹⁄₄	4 ³⁄₈	¹⁄₁₆	4.239 ± 0.030	.070 ± 0.003	107.67 ± 0.76	1.78 ± 0.08
-047	4 ¹⁄₂	4 ⁵⁄₈	¹⁄₁₆	4.489 ± 0.030	.070 ± 0.003	114.02 ± 0.76	1.78 ± 0.08
-048	4 ³⁄₄	4 ⁷⁄₈	¹⁄₁₆	4.739 ± 0.030	.070 ± 0.003	120.37 ± 0.76	1.78 ± 0.08
-049	5	5 ¹⁄₈	¹⁄₁₆	4.989 ± 0.037	.070 ± 0.003	126.72 ± 0.94	1.78 ± 0.08
-050	5 ¹⁄₄	5 ³⁄₈	¹⁄₁₆	5.239 ± 0.037	.070 ± 0.003	133.07 ± 0.94	1.78 ± 0.08

O-rings with a nominal cross-section of ³⁄₃₂ inch (-1##)

Size reference code (dash number)	Nominal size in inches			Decimal size in inches		Decimal size in millimeters
Size reference code (dash number)	ID	OD	Cross-section	ID	Cross-section	ID	Cross-section
-102	¹⁄₁₆	¹⁄₄	³⁄₃₂	.049 ± 0.005	.103 ± 0.003	1.24 ± 0.13	2.62 ± 0.08
-103	³⁄₃₂	⁹⁄₃₂	³⁄₃₂	.081 ± 0.005	.103 ± 0.003	2.06 ± 0.13	2.62 ± 0.08
-104	¹⁄₈	⁵⁄₁₆	³⁄₃₂	.112 ± 0.005	.103 ± 0.003	2.84 ± 0.13	2.62 ± 0.08
-105	⁵⁄₃₂	¹¹⁄₃₂	³⁄₃₂	.143 ± 0.005	.103 ± 0.003	3.63 ± 0.13	2.62 ± 0.08
-106	³⁄₁₆	³⁄₈	³⁄₃₂	.174 ± 0.005	.103 ± 0.003	4.42 ± 0.13	2.62 ± 0.08
-107	⁷⁄₃₂	¹³⁄₃₂	³⁄₃₂	.206 ± 0.005	.103 ± 0.003	5.23 ± 0.13	2.62 ± 0.08
-108	¹⁄₄	⁷⁄₁₆	³⁄₃₂	.237 ± 0.005	.103 ± 0.003	6.02 ± 0.13	2.62 ± 0.08
-109	⁵⁄₁₆	¹⁄₂	³⁄₃₂	.299 ± 0.005	.103 ± 0.003	7.59 ± 0.13	2.62 ± 0.08
-110	³⁄₈	⁹⁄₁₆	³⁄₃₂	.362 ± 0.005	.103 ± 0.003	9.19 ± 0.13	2.62 ± 0.08
-111	⁷⁄₁₆	⁵⁄₈	³⁄₃₂	.424 ± 0.005	.103 ± 0.003	10.77 ± 0.13	2.62 ± 0.08
-112	¹⁄₂	¹¹⁄₁₆	³⁄₃₂	.487 ± 0.005	.103 ± 0.003	12.37 ± 0.13	2.62 ± 0.08
-113	⁹⁄₁₆	³⁄₄	³⁄₃₂	.549 ± 0.007	.103 ± 0.003	13.94 ± 0.18	2.62 ± 0.08
-114	⁵⁄₈	¹³⁄₁₆	³⁄₃₂	.612 ± 0.009	.103 ± 0.003	15.54 ± 0.23	2.62 ± 0.08
-115	¹¹⁄₁₆	⁷⁄₈	³⁄₃₂	.674 ± 0.009	.103 ± 0.003	17.12 ± 0.23	2.62 ± 0.08
-116	³⁄₄	¹⁵⁄₁₆	³⁄₃₂	.737 ± 0.009	.103 ± 0.003	18.72 ± 0.23	2.62 ± 0.08
-117	¹³⁄₁₆	1	³⁄₃₂	.799 ± 0.010	.103 ± 0.003	20.29 ± 0.25	2.62 ± 0.08
-118	⁷⁄₈	1 ¹⁄₁₆	³⁄₃₂	.862 ± 0.010	.103 ± 0.003	21.89 ± 0.25	2.62 ± 0.08
-119	¹⁵⁄₁₆	1 ¹⁄₈	³⁄₃₂	.924 ± 0.010	.103 ± 0.003	23.47 ± 0.25	2.62 ± 0.08
-120	1	1 ³⁄₁₆	³⁄₃₂	.987 ± 0.010	.103 ± 0.003	25.07 ± 0.25	2.62 ± 0.08
-121	1 ¹⁄₁₆	1 ¹⁄₄	³⁄₃₂	1.049 ± 0.010	.103 ± 0.003	26.64 ± 0.25	2.62 ± 0.08
-122	1 ¹⁄₈	1 ⁵⁄₁₆	³⁄₃₂	1.112 ± 0.010	.103 ± 0.003	28.24 ± 0.25	2.62 ± 0.08
-123	1 ³⁄₁₆	1 ³⁄₈	³⁄₃₂	1.174 ± 0.012	.103 ± 0.003	29.82 ± 0.30	2.62 ± 0.08
-124	1 ¹⁄₄	1 ⁷⁄₁₆	³⁄₃₂	1.237 ± 0.012	.103 ± 0.003	31.42 ± 0.30	2.62 ± 0.08
-125	1 ⁵⁄₁₆	1 ¹⁄₂	³⁄₃₂	1.299 ± 0.012	.103 ± 0.003	32.99 ± 0.30	2.62 ± 0.08
-126	1 ³⁄₈	1 ⁹⁄₁₆	³⁄₃₂	1.362 ± 0.012	.103 ± 0.003	34.59 ± 0.30	2.62 ± 0.08
-127	1 ⁷⁄₁₆	1 ⁵⁄₈	³⁄₃₂	1.424 ± 0.012	.103 ± 0.003	36.17 ± 0.30	2.62 ± 0.08
-128	1 ¹⁄₂	1 ¹¹⁄₁₆	³⁄₃₂	1.487 ± 0.012	.103 ± 0.003	37.77 ± 0.30	2.62 ± 0.08
-129	1 ⁹⁄₁₆	1 ³⁄₄	³⁄₃₂	1.549 ± 0.015	.103 ± 0.003	39.34 ± 0.38	2.62 ± 0.08
-130	1 ⁵⁄₈	1 ¹³⁄₁₆	³⁄₃₂	1.612 ± 0.015	.103 ± 0.003	40.94 ± 0.38	2.62 ± 0.08
-131	1 ¹¹⁄₁₆	1 ⁷⁄₈	³⁄₃₂	1.674 ± 0.015	.103 ± 0.003	42.52 ± 0.38	2.62 ± 0.08
-132	1 ³⁄₄	1 ¹⁵⁄₁₆	³⁄₃₂	1.737 ± 0.015	.103 ± 0.003	44.12 ± 0.38	2.62 ± 0.08
-133	1 ¹³⁄₁₆	2	³⁄₃₂	1.799 ± 0.015	.103 ± 0.003	45.69 ± 0.38	2.62 ± 0.08
-134	1 ⁷⁄₈	2 ¹⁄₁₆	³⁄₃₂	1.862 ± 0.015	.103 ± 0.003	47.29 ± 0.38	2.62 ± 0.08
-135	1 ¹⁵⁄₁₆	2 ¹⁄₈	³⁄₃₂	1.925 ± 0.017	.103 ± 0.003	48.90 ± 0.43	2.62 ± 0.08
-136	2	2 ³⁄₁₆	³⁄₃₂	1.987 ± 0.017	.103 ± 0.003	50.47 ± 0.43	2.62 ± 0.08
-137	2 ¹⁄₁₆	2 ¹⁄₄	³⁄₃₂	2.050 ± 0.017	.103 ± 0.003	52.07 ± 0.43	2.62 ± 0.08
-138	2 ¹⁄₈	2 ⁵⁄₁₆	³⁄₃₂	2.112 ± 0.017	.103 ± 0.003	53.64 ± 0.43	2.62 ± 0.08
-139	2 ³⁄₁₆	2 ³⁄₈	³⁄₃₂	2.175 ± 0.017	.103 ± 0.003	55.25 ± 0.43	2.62 ± 0.08
-140	2 ¹⁄₄	2 ⁷⁄₁₆	³⁄₃₂	2.237 ± 0.017	.103 ± 0.003	56.82 ± 0.43	2.62 ± 0.08
-141	2 ⁵⁄₁₆	2 ¹⁄₂	³⁄₃₂	2.300 ± 0.020	.103 ± 0.003	58.42 ± 0.51	2.62 ± 0.08
-142	2 ³⁄₈	2 ⁹⁄₁₆	³⁄₃₂	2.362 ± 0.020	.103 ± 0.003	59.99 ± 0.51	2.62 ± 0.08
-143	2 ⁷⁄₁₆	2 ⁵⁄₈	³⁄₃₂	2.425 ± 0.020	.103 ± 0.003	61.60 ± 0.51	2.62 ± 0.08
-144	2 ¹⁄₂	2 ¹¹⁄₁₆	³⁄₃₂	2.487 ± 0.020	.103 ± 0.003	63.17 ± 0.51	2.62 ± 0.08
-145	2 ⁹⁄₁₆	2 ³⁄₄	³⁄₃₂	2.550 ± 0.020	.103 ± 0.003	64.77 ± 0.51	2.62 ± 0.08
-146	2 ⁵⁄₈	2 ¹³⁄₁₆	³⁄₃₂	2.612 ± 0.020	.103 ± 0.003	66.34 ± 0.51	2.62 ± 0.08
-147	2 ¹¹⁄₁₆	2 ⁷⁄₈	³⁄₃₂	2.675 ± 0.022	.103 ± 0.003	67.95 ± 0.56	2.62 ± 0.08
-148	2 ³⁄₄	2 ¹⁵⁄₁₆	³⁄₃₂	2.737 ± 0.022	.103 ± 0.003	69.52 ± 0.56	2.62 ± 0.08
-149	2 ¹³⁄₁₆	3	³⁄₃₂	2.800 ± 0.022	.103 ± 0.003	71.12 ± 0.56	2.62 ± 0.08
-150	2 ⁷⁄₈	3 ¹⁄₁₆	³⁄₃₂	2.862 ± 0.022	.103 ± 0.003	72.69 ± 0.56	2.62 ± 0.08
-151	3	3 ³⁄₁₆	³⁄₃₂	2.987 ± 0.024	.103 ± 0.003	75.87 ± 0.61	2.62 ± 0.08
-152	3 ¹⁄₄	3 ⁷⁄₁₆	³⁄₃₂	3.237 ± 0.024	.103 ± 0.003	82.22 ± 0.61	2.62 ± 0.08
-153	3 ¹⁄₂	3 ¹¹⁄₁₆	³⁄₃₂	3.487 ± 0.024	.103 ± 0.003	88.57 ± 0.61	2.62 ± 0.08
-154	3 ³⁄₄	3 ¹⁵⁄₁₆	³⁄₃₂	3.737 ± 0.028	.103 ± 0.003	94.92 ± 0.71	2.62 ± 0.08
-155	4	4 ³⁄₁₆	³⁄₃₂	3.987 ± 0.028	.103 ± 0.003	101.27 ± 0.71	2.62 ± 0.08
-156	4 ¹⁄₄	4 ⁷⁄₁₆	³⁄₃₂	4.237 ± 0.030	.103 ± 0.003	107.62 ± 0.76	2.62 ± 0.08
-157	4 ¹⁄₂	4 ¹¹⁄₁₆	³⁄₃₂	4.487 ± 0.030	.103 ± 0.003	113.97 ± 0.76	2.62 ± 0.08
-158	4 ³⁄₄	4 ¹⁵⁄₁₆	³⁄₃₂	4.737 ± 0.030	.103 ± 0.003	120.32 ± 0.76	2.62 ± 0.08
-159	5	5 ³⁄₁₆	³⁄₃₂	4.987 ± 0.035	.103 ± 0.003	126.67 ± 0.89	2.62 ± 0.08
-160	5 ¹⁄₄	5 ⁷⁄₁₆	³⁄₃₂	5.237 ± 0.035	.103 ± 0.003	133.02 ± 0.89	2.62 ± 0.08
-161	5 ¹⁄₂	5 ¹¹⁄₁₆	³⁄₃₂	5.487 ± 0.035	.103 ± 0.003	139.37 ± 0.89	2.62 ± 0.08
-162	5 ³⁄₄	5 ¹⁵⁄₁₆	³⁄₃₂	5.737 ± 0.035	.103 ± 0.003	145.72 ± 0.89	2.62 ± 0.08
-163	6	6 ³⁄₁₆	³⁄₃₂	5.987 ± 0.035	.103 ± 0.003	152.07 ± 0.89	2.62 ± 0.08
-164	6 ¹⁄₄	6 ⁷⁄₁₆	³⁄₃₂	6.237 ± 0.040	.103 ± 0.003	158.42 ± 1.02	2.62 ± 0.08
-165	6 ¹⁄₂	6 ¹¹⁄₁₆	³⁄₃₂	6.487 ± 0.040	.103 ± 0.003	164.77 ± 1.02	2.62 ± 0.08
-166	6 ³⁄₄	6 ¹⁵⁄₁₆	³⁄₃₂	6.737 ± 0.040	.103 ± 0.003	171.12 ± 1.02	2.62 ± 0.08
-167	7	7 ³⁄₁₆	³⁄₃₂	6.987 ± 0.040	.103 ± 0.003	177.47 ± 1.02	2.62 ± 0.08
-168	7 ¹⁄₄	7 ⁷⁄₁₆	³⁄₃₂	7.237 ± 0.045	.103 ± 0.003	183.82 ± 1.14	2.62 ± 0.08
-169	7 ¹⁄₂	7 ¹¹⁄₁₆	³⁄₃₂	7.487 ± 0.045	.103 ± 0.003	190.17 ± 1.14	2.62 ± 0.08
-170	7 ³⁄₄	7 ¹⁵⁄₁₆	³⁄₃₂	7.737 ± 0.045	.103 ± 0.003	196.52 ± 1.14	2.62 ± 0.08
-171	8	8 ³⁄₁₆	³⁄₃₂	7.987 ± 0.045	.103 ± 0.003	202.87 ± 1.14	2.62 ± 0.08
-172	8 ¹⁄₄	8 ⁷⁄₁₆	³⁄₃₂	8.237 ± 0.050	.103 ± 0.003	209.22 ± 1.27	2.62 ± 0.08
-173	8 ¹⁄₂	8 ¹¹⁄₁₆	³⁄₃₂	8.487 ± 0.050	.103 ± 0.003	215.57 ± 1.27	2.62 ± 0.08
-174	8 ³⁄₄	8 ¹⁵⁄₁₆	³⁄₃₂	8.737 ± 0.050	.103 ± 0.003	221.92 ± 1.27	2.62 ± 0.08
-175	9	9 ³⁄₁₆	³⁄₃₂	8.987 ± 0.050	.103 ± 0.003	228.27 ± 1.27	2.62 ± 0.08
-176	9 ¹⁄₄	9 ⁷⁄₁₆	³⁄₃₂	9.237 ± 0.055	.103 ± 0.003	234.62 ± 1.40	2.62 ± 0.08
-177	9 ¹⁄₂	9 ¹¹⁄₁₆	³⁄₃₂	9.487 ± 0.055	.103 ± 0.003	240.97 ± 1.40	2.62 ± 0.08
-178	9 ³⁄₄	9 ¹⁵⁄₁₆	³⁄₃₂	9.737 ± 0.055	.103 ± 0.003	247.32 ± 1.40	2.62 ± 0.08

O-rings with a nominal cross-section of ¹⁄₈ inch (-2##)

Size reference code (dash number)	Nominal size in inches			Decimal size in inches		Decimal size in millimeters
Size reference code (dash number)	ID	OD	Cross-section	ID	Cross-section	ID	Cross-section
-201	³⁄₁₆	⁷⁄₁₆	¹⁄₈	.171 ± 0.005	.139 ± 0.004	4.34 ± 0.13	3.53 ± 0.10
-202	¹⁄₄	¹⁄₂	¹⁄₈	.234 ± 0.005	.139 ± 0.004	5.94 ± 0.13	3.53 ± 0.10
-203	⁵⁄₁₆	⁹⁄₁₆	¹⁄₈	.296 ± 0.005	.139 ± 0.004	7.52 ± 0.13	3.53 ± 0.10
-204	³⁄₈	⁵⁄₈	¹⁄₈	.359 ± 0.005	.139 ± 0.004	9.12 ± 0.13	3.53 ± 0.10
-205	⁷⁄₁₆	¹¹⁄₁₆	¹⁄₈	.421 ± 0.005	.139 ± 0.004	10.69 ± 0.13	3.53 ± 0.10
-206	¹⁄₂	³⁄₄	¹⁄₈	.484 ± 0.005	.139 ± 0.004	12.29 ± 0.13	3.53 ± 0.10
-207	⁹⁄₁₆	¹³⁄₁₆	¹⁄₈	.546 ± 0.007	.139 ± 0.004	13.87 ± 0.18	3.53 ± 0.10
-208	⁵⁄₈	⁷⁄₈	¹⁄₈	.609 ± 0.009	.139 ± 0.004	15.47 ± 0.23	3.53 ± 0.10
-209	¹¹⁄₁₆	¹⁵⁄₁₆	¹⁄₈	.671 ± 0.009	.139 ± 0.004	17.04 ± 0.23	3.53 ± 0.10
-210	³⁄₄	1	¹⁄₈	.734 ± 0.010	.139 ± 0.004	18.64 ± 0.25	3.53 ± 0.10
-211	¹³⁄₁₆	1 ¹⁄₁₆	¹⁄₈	.796 ± 0.010	.139 ± 0.004	20.22 ± 0.25	3.53 ± 0.10
-212	⁷⁄₈	1 ¹⁄₈	¹⁄₈	.859 ± 0.010	.139 ± 0.004	21.82 ± 0.25	3.53 ± 0.10
-213	¹⁵⁄₁₆	1 ³⁄₁₆	¹⁄₈	.921 ± 0.010	.139 ± 0.004	23.39 ± 0.25	3.53 ± 0.10
-214	1	1 ¹⁄₄	¹⁄₈	.984 ± 0.010	.139 ± 0.004	24.99 ± 0.25	3.53 ± 0.10
-215	1 ¹⁄₁₆	1 ⁵⁄₁₆	¹⁄₈	1.046 ± 0.010	.139 ± 0.004	26.57 ± 0.25	3.53 ± 0.10
-216	1 ¹⁄₈	1 ³⁄₈	¹⁄₈	1.109 ± 0.012	.139 ± 0.004	28.17 ± 0.30	3.53 ± 0.10
-217	1 ³⁄₁₆	1 ⁷⁄₁₆	¹⁄₈	1.171 ± 0.012	.139 ± 0.004	29.74 ± 0.30	3.53 ± 0.10
-218	1 ¹⁄₄	1 ¹⁄₂	¹⁄₈	1.234 ± 0.012	.139 ± 0.004	31.34 ± 0.30	3.53 ± 0.10
-219	1 ⁵⁄₁₆	1 ⁹⁄₁₆	¹⁄₈	1.296 ± 0.012	.139 ± 0.004	32.92 ± 0.30	3.53 ± 0.10
-220	1 ³⁄₈	1 ⁵⁄₈	¹⁄₈	1.359 ± 0.012	.139 ± 0.004	34.52 ± 0.30	3.53 ± 0.10
-221	1 ⁷⁄₁₆	1 ¹¹⁄₁₆	¹⁄₈	1.421 ± 0.012	.139 ± 0.004	36.09 ± 0.30	3.53 ± 0.10
-222	1 ¹⁄₂	1 ³⁄₄	¹⁄₈	1.484 ± 0.015	.139 ± 0.004	37.69 ± 0.38	3.53 ± 0.10
-223	1 ⁵⁄₈	1 ⁷⁄₈	¹⁄₈	1.609 ± 0.015	.139 ± 0.004	40.87 ± 0.38	3.53 ± 0.10
-224	1 ³⁄₄	2	¹⁄₈	1.734 ± 0.015	.139 ± 0.004	44.04 ± 0.38	3.53 ± 0.10
-225	1 ⁷⁄₈	2 ¹⁄₈	¹⁄₈	1.859 ± 0.018	.139 ± 0.004	47.22 ± 0.46	3.53 ± 0.10
-226	2	2 ¹⁄₄	¹⁄₈	1.984 ± 0.018	.139 ± 0.004	50.39 ± 0.46	3.53 ± 0.10
-227	2 ¹⁄₈	2 ³⁄₈	¹⁄₈	2.109 ± 0.018	.139 ± 0.004	53.57 ± 0.46	3.53 ± 0.10
-228	2 ¹⁄₄	2 ¹⁄₂	¹⁄₈	2.234 ± 0.020	.139 ± 0.004	56.74 ± 0.51	3.53 ± 0.10
-229	2 ³⁄₈	2 ⁵⁄₈	¹⁄₈	2.359 ± 0.020	.139 ± 0.004	59.92 ± 0.51	3.53 ± 0.10
-230	2 ¹⁄₂	2 ³⁄₄	¹⁄₈	2.484 ± 0.020	.139 ± 0.004	63.09 ± 0.51	3.53 ± 0.10
-231	2 ⁵⁄₈	2 ⁷⁄₈	¹⁄₈	2.609 ± 0.020	.139 ± 0.004	66.27 ± 0.51	3.53 ± 0.10
-232	2 ³⁄₄	3	¹⁄₈	2.734 ± 0.024	.139 ± 0.004	69.44 ± 0.61	3.53 ± 0.10
-233	2 ⁷⁄₈	3 ¹⁄₈	¹⁄₈	2.859 ± 0.024	.139 ± 0.004	72.62 ± 0.61	3.53 ± 0.10
-234	3	3 ¹⁄₄	¹⁄₈	2.984 ± 0.024	.139 ± 0.004	75.79 ± 0.61	3.53 ± 0.10
-235	3 ¹⁄₈	3 ³⁄₈	¹⁄₈	3.109 ± 0.024	.139 ± 0.004	78.97 ± 0.61	3.53 ± 0.10
-236	3 ¹⁄₄	3 ¹⁄₂	¹⁄₈	3.234 ± 0.024	.139 ± 0.004	82.14 ± 0.61	3.53 ± 0.10
-237	3 ³⁄₈	3 ⁵⁄₈	¹⁄₈	3.359 ± 0.024	.139 ± 0.004	85.32 ± 0.61	3.53 ± 0.10
-238	3 ¹⁄₂	3 ³⁄₄	¹⁄₈	3.484 ± 0.024	.139 ± 0.004	88.49 ± 0.61	3.53 ± 0.10
-239	3 ⁵⁄₈	3 ⁷⁄₈	¹⁄₈	3.609 ± 0.028	.139 ± 0.004	91.67 ± 0.71	3.53 ± 0.10
-240	3 ³⁄₄	4	¹⁄₈	3.734 ± 0.028	.139 ± 0.004	94.84 ± 0.71	3.53 ± 0.10
-241	3 ⁷⁄₈	4 ¹⁄₈	¹⁄₈	3.859 ± 0.028	.139 ± 0.004	98.02 ± 0.71	3.53 ± 0.10
-242	4	4 ¹⁄₄	¹⁄₈	3.984 ± 0.028	.139 ± 0.004	101.19 ± 0.71	3.53 ± 0.10
-243	4 ¹⁄₈	4 ³⁄₈	¹⁄₈	4.109 ± 0.028	.139 ± 0.004	104.37 ± 0.71	3.53 ± 0.10
-244	4 ¹⁄₄	4 ¹⁄₂	¹⁄₈	4.234 ± 0.030	.139 ± 0.004	107.54 ± 0.76	3.53 ± 0.10
-245	4 ³⁄₈	4 ⁵⁄₈	¹⁄₈	4.359 ± 0.030	.139 ± 0.004	110.72 ± 0.76	3.53 ± 0.10
-246	4 ¹⁄₂	4 ³⁄₄	¹⁄₈	4.484 ± 0.030	.139 ± 0.004	113.89 ± 0.76	3.53 ± 0.10
-247	4 ⁵⁄₈	4 ⁷⁄₈	¹⁄₈	4.609 ± 0.030	.139 ± 0.004	117.07 ± 0.76	3.53 ± 0.10
-248	4 ³⁄₄	5	¹⁄₈	4.734 ± 0.030	.139 ± 0.004	120.24 ± 0.76	3.53 ± 0.10
-249	4 ⁷⁄₈	5 ¹⁄₈	¹⁄₈	4.859 ± 0.035	.139 ± 0.004	123.42 ± 0.89	3.53 ± 0.10
-250	5	5 ¹⁄₄	¹⁄₈	4.984 ± 0.035	.139 ± 0.004	126.59 ± 0.89	3.53 ± 0.10
-251	5 ¹⁄₈	5 ³⁄₈	¹⁄₈	5.109 ± 0.035	.139 ± 0.004	129.77 ± 0.89	3.53 ± 0.10
-252	5 ¹⁄₄	5 ¹⁄₂	¹⁄₈	5.234 ± 0.035	.139 ± 0.004	132.94 ± 0.89	3.53 ± 0.10
-253	5 ³⁄₈	5 ⁵⁄₈	¹⁄₈	5.359 ± 0.035	.139 ± 0.004	136.12 ± 0.89	3.53 ± 0.10
-254	5 ¹⁄₂	5 ³⁄₄	¹⁄₈	5.484 ± 0.035	.139 ± 0.004	139.29 ± 0.89	3.53 ± 0.10
-255	5 ⁵⁄₈	5 ⁷⁄₈	¹⁄₈	5.609 ± 0.035	.139 ± 0.004	142.47 ± 0.89	3.53 ± 0.10
-256	5 ³⁄₄	6	¹⁄₈	5.734 ± 0.035	.139 ± 0.004	145.64 ± 0.89	3.53 ± 0.10
-257	5 ⁷⁄₈	6 ¹⁄₈	¹⁄₈	5.859 ± 0.035	.139 ± 0.004	148.82 ± 0.89	3.53 ± 0.10
-258	6	6 ¹⁄₄	¹⁄₈	5.984 ± 0.035	.139 ± 0.004	151.99 ± 0.89	3.53 ± 0.10
-259	6 ¹⁄₄	6 ¹⁄₂	¹⁄₈	6.234 ± 0.040	.139 ± 0.004	158.34 ± 1.02	3.53 ± 0.10
-260	6 ¹⁄₂	6 ³⁄₄	¹⁄₈	6.484 ± 0.040	.139 ± 0.004	164.69 ± 1.02	3.53 ± 0.10
-261	6 ³⁄₄	7	¹⁄₈	6.734 ± 0.040	.139 ± 0.004	171.04 ± 1.02	3.53 ± 0.10
-262	7	7 ¹⁄₄	¹⁄₈	6.984 ± 0.040	.139 ± 0.004	177.39 ± 1.02	3.53 ± 0.10
-263	7 ¹⁄₄	7 ¹⁄₂	¹⁄₈	7.234 ± 0.045	.139 ± 0.004	183.74 ± 1.14	3.53 ± 0.10
-264	7 ¹⁄₂	7 ³⁄₄	¹⁄₈	7.484 ± 0.045	.139 ± 0.004	190.09 ± 1.14	3.53 ± 0.10
-265	7 ³⁄₄	8	¹⁄₈	7.734 ± 0.045	.139 ± 0.004	196.44 ± 1.14	3.53 ± 0.10
-266	8	8 ¹⁄₄	¹⁄₈	7.984 ± 0.045	.139 ± 0.004	202.79 ± 1.14	3.53 ± 0.10
-267	8 ¹⁄₄	8 ¹⁄₂	¹⁄₈	8.234 ± 0.050	.139 ± 0.004	209.14 ± 1.27	3.53 ± 0.10
-268	8 ¹⁄₂	8 ³⁄₄	¹⁄₈	8.484 ± 0.050	.139 ± 0.004	215.49 ± 1.27	3.53 ± 0.10
-269	8 ³⁄₄	9	¹⁄₈	8.734 ± 0.050	.139 ± 0.004	221.84 ± 1.27	3.53 ± 0.10
-270	9	9 ¹⁄₄	¹⁄₈	8.984 ± 0.050	.139 ± 0.004	228.19 ± 1.27	3.53 ± 0.10
-271	9 ¹⁄₄	9 ¹⁄₂	¹⁄₈	9.234 ± 0.055	.139 ± 0.004	234.54 ± 1.40	3.53 ± 0.10
-272	9 ¹⁄₂	9 ³⁄₄	¹⁄₈	9.484 ± 0.055	.139 ± 0.004	240.89 ± 1.40	3.53 ± 0.10
-273	9 ³⁄₄	10	¹⁄₈	9.734 ± 0.055	.139 ± 0.004	247.24 ± 1.40	3.53 ± 0.10
-274	10	10 ¹⁄₄	¹⁄₈	9.984 ± 0.055	.139 ± 0.004	253.59 ± 1.40	3.53 ± 0.10
-275	10 ¹⁄₂	10 ³⁄₄	¹⁄₈	10.484 ± 0.055	.139 ± 0.004	266.29 ± 1.40	3.53 ± 0.10
-276	11	11 ¹⁄₄	¹⁄₈	10.984 ± 0.065	.139 ± 0.004	278.99 ± 1.65	3.53 ± 0.10
-277	11 ¹⁄₂	11 ³⁄₄	¹⁄₈	11.484 ± 0.065	.139 ± 0.004	291.69 ± 1.65	3.53 ± 0.10
-278	12	12 ¹⁄₄	¹⁄₈	11.984 ± 0.065	.139 ± 0.004	304.39 ± 1.65	3.53 ± 0.10
-279	13	13 ¹⁄₄	¹⁄₈	12.984 ± 0.065	.139 ± 0.004	329.79 ± 1.65	3.53 ± 0.10
-280	14	14 ¹⁄₄	¹⁄₈	13.984 ± 0.065	.139 ± 0.004	355.19 ± 1.65	3.53 ± 0.10
-281	15	15 ¹⁄₄	¹⁄₈	14.984 ± 0.065	.139 ± 0.004	380.59 ± 1.65	3.53 ± 0.10
-282	16	16 ¹⁄₄	¹⁄₈	15.955 ± 0.075	.139 ± 0.004	405.26 ± 1.91	3.53 ± 0.10
-283	17	17 ¹⁄₄	¹⁄₈	16.955 ± 0.080	.139 ± 0.004	430.66 ± 2.03	3.53 ± 0.10
-284	18	18 ¹⁄₄	¹⁄₈	17.955 ± 0.085	.139 ± 0.004	456.06 ± 2.16	3.53 ± 0.10

O-rings with a nominal cross-section of ³⁄₁₆ inch (-3##)

Size reference code (dash number)	Nominal size in inches			Decimal size in inches		Decimal size in millimeters
Size reference code (dash number)	ID	OD	Cross-section	ID	Cross-section	ID	Cross-section
-309	⁷⁄₁₆	¹³⁄₁₆	³⁄₁₆	.412 ± 0.005	.210 ± 0.005	10.46 ± 0.13	5.33 ± 0.13
-310	¹⁄₂	⁷⁄₈	³⁄₁₆	.475 ± 0.005	.210 ± 0.005	12.07 ± 0.13	5.33 ± 0.13
-311	⁹⁄₁₆	15-16	³⁄₁₆	.537 ± 0.007	.210 ± 0.005	13.64 ± 0.18	5.33 ± 0.13
-312	⁵⁄₈	1	³⁄₁₆	.600 ± 0.009	.210 ± 0.005	15.24 ± 0.23	5.33 ± 0.13
-313	¹¹⁄₁₆	1 ¹⁄₁₆	³⁄₁₆	.662 ± 0.009	.210 ± 0.005	16.81 ± 0.23	5.33 ± 0.13
-314	³⁄₄	1 ¹⁄₈	³⁄₁₆	.725 ± 0.010	.210 ± 0.005	18.42 ± 0.25	5.33 ± 0.13
-315	¹³⁄₁₆	1 ³⁄₁₆	³⁄₁₆	.787 ± 0.010	.210 ± 0.005	19.99 ± 0.25	5.33 ± 0.13
-316	⁷⁄₈	1 ¹⁄₄	³⁄₁₆	.850 ± 0.010	.210 ± 0.005	21.59 ± 0.25	5.33 ± 0.13
-317	¹⁵⁄₁₆	1 ⁵⁄₁₆	³⁄₁₆	.912 ± 0.010	.210 ± 0.005	23.16 ± 0.25	5.33 ± 0.13
-318	1	1 ³⁄₈	³⁄₁₆	.975 ± 0.010	.210 ± 0.005	24.77 ± 0.25	5.33 ± 0.13
-319	1 ¹⁄₁₆	1 ⁷⁄₁₆	³⁄₁₆	1.037 ± 0.010	.210 ± 0.005	26.34 ± 0.25	5.33 ± 0.13
-320	1 ¹⁄₈	1 ¹⁄₂	³⁄₁₆	1.100 ± 0.012	.210 ± 0.005	27.94 ± 0.30	5.33 ± 0.13
-321	1 ³⁄₁₆	1 ⁹⁄₁₆	³⁄₁₆	1.162 ± 0.012	.210 ± 0.005	29.51 ± 0.30	5.33 ± 0.13
-322	1 ¹⁄₄	1 ⁵⁄₈	³⁄₁₆	1.225 ± 0.012	.210 ± 0.005	31.12 ± 0.30	5.33 ± 0.13
-323	1 ⁵⁄₁₆	1 ¹¹⁄₁₆	³⁄₁₆	1.287 ± 0.012	.210 ± 0.005	32.69 ± 0.30	5.33 ± 0.13
-324	1 ³⁄₈	1 ³⁄₄	³⁄₁₆	1.350 ± 0.012	.210 ± 0.005	34.29 ± 0.30	5.33 ± 0.13
-325	1 ¹⁄₂	1 ⁷⁄₈	³⁄₁₆	1.475 ± 0.015	.210 ± 0.005	37.47 ± 0.38	5.33 ± 0.13
-326	1 ⁵⁄₈	2	³⁄₁₆	1.600 ± 0.015	.210 ± 0.005	40.64 ± 0.38	5.33 ± 0.13
-327	1 ³⁄₄	2 ¹⁄₈	³⁄₁₆	1.725 ± 0.015	.210 ± 0.005	43.82 ± 0.38	5.33 ± 0.13
-328	1 ⁷⁄₈	2 ¹⁄₄	³⁄₁₆	1.850 ± 0.015	.210 ± 0.005	46.99 ± 0.38	5.33 ± 0.13
-329	2	2 ³⁄₈	³⁄₁₆	1.975 ± 0.018	.210 ± 0.005	50.17 ± 0.46	5.33 ± 0.13
-330	2 ¹⁄₈	2 ¹⁄₂	³⁄₁₆	2.100 ± 0.018	.210 ± 0.005	53.34 ± 0.46	5.33 ± 0.13
-331	2 ¹⁄₄	2 ⁵⁄₈	³⁄₁₆	2.225 ± 0.018	.210 ± 0.005	56.52 ± 0.46	5.33 ± 0.13
-332	2 ³⁄₈	2 ³⁄₄	³⁄₁₆	2.350 ± 0.018	.210 ± 0.005	59.69 ± 0.46	5.33 ± 0.13
-333	2 ¹⁄₂	2 ⁷⁄₈	³⁄₁₆	2.475 ± 0.020	.210 ± 0.005	62.87 ± 0.51	5.33 ± 0.13
-334	2 ⁵⁄₈	3	³⁄₁₆	2.600 ± 0.020	.210 ± 0.005	66.04 ± 0.51	5.33 ± 0.13
-335	2 ³⁄₄	3 ¹⁄₈	³⁄₁₆	2.725 ± 0.020	.210 ± 0.005	69.22 ± 0.51	5.33 ± 0.13
-336	2 ⁷⁄₈	3 ¹⁄₄	³⁄₁₆	2.850 ± 0.020	.210 ± 0.005	72.39 ± 0.51	5.33 ± 0.13
-337	3	3 ³⁄₈	³⁄₁₆	2.975 ± 0.024	.210 ± 0.005	75.57 ± 0.61	5.33 ± 0.13
-338	3 ¹⁄₈	3 ¹⁄₂	³⁄₁₆	3.100 ± 0.024	.210 ± 0.005	78.74 ± 0.61	5.33 ± 0.13
-339	3 ¹⁄₄	3 ⁵⁄₈	³⁄₁₆	3.225 ± 0.024	.210 ± 0.005	81.92 ± 0.61	5.33 ± 0.13
-340	3 ³⁄₈	3 ³⁄₄	³⁄₁₆	3.350 ± 0.024	.210 ± 0.005	85.09 ± 0.61	5.33 ± 0.13
-341	3 ¹⁄₂	3 ⁷⁄₈	³⁄₁₆	3.475 ± 0.024	.210 ± 0.005	88.27 ± 0.61	5.33 ± 0.13
-342	3 ⁵⁄₈	4	³⁄₁₆	3.600 ± 0.028	.210 ± 0.005	91.44 ± 0.71	5.33 ± 0.13
-343	3 ³⁄₄	4 ¹⁄₈	³⁄₁₆	3.725 ± 0.028	.210 ± 0.005	94.62 ± 0.71	5.33 ± 0.13
-344	3 ⁷⁄₈	4 ¹⁄₄	³⁄₁₆	3.850 ± 0.028	.210 ± 0.005	97.79 ± 0.71	5.33 ± 0.13
-345	4	4 ³⁄₈	³⁄₁₆	3.975 ± 0.028	.210 ± 0.005	100.97 ± 0.71	5.33 ± 0.13
-346	4 ¹⁄₈	4 ¹⁄₂	³⁄₁₆	4.100 ± 0.028	.210 ± 0.005	104.14 ± 0.71	5.33 ± 0.13
-347	4 ¹⁄₄	4 ⁵⁄₈	³⁄₁₆	4.225 ± 0.030	.210 ± 0.005	107.32 ± 0.76	5.33 ± 0.13
-348	4 ³⁄₈	4 ³⁄₄	³⁄₁₆	4.350 ± 0.030	.210 ± 0.005	110.49 ± 0.76	5.33 ± 0.13
-349	4 ¹⁄₂	4 ⁷⁄₈	³⁄₁₆	4.475 ± 0.030	.210 ± 0.005	113.67 ± 0.76	5.33 ± 0.13
-350	4 ⁵⁄₈	5	³⁄₁₆	4.600 ± 0.030	.210 ± 0.005	116.84 ± 0.76	5.33 ± 0.13
-351	4 ³⁄₄	5 ¹⁄₈	³⁄₁₆	4.725 ± 0.030	.210 ± 0.005	120.02 ± 0.76	5.33 ± 0.13
-352	4 ⁷⁄₈	5 ¹⁄₄	³⁄₁₆	4.850 ± 0.030	.210 ± 0.005	123.19 ± 0.76	5.33 ± 0.13
-353	5	5 ³⁄₈	³⁄₁₆	4.975 ± 0.037	.210 ± 0.005	126.37 ± 0.94	5.33 ± 0.13
-354	5 ¹⁄₈	5 ¹⁄₂	³⁄₁₆	5.100 ± 0.037	.210 ± 0.005	129.54 ± 0.94	5.33 ± 0.13
-355	5 ¹⁄₄	5 ⁵⁄₈	³⁄₁₆	5.225 ± 0.037	.210 ± 0.005	132.72 ± 0.94	5.33 ± 0.13
-356	5 ³⁄₈	5 ³⁄₄	³⁄₁₆	5.350 ± 0.037	.210 ± 0.005	135.89 ± 0.94	5.33 ± 0.13
-357	5 ¹⁄₂	5 ⁷⁄₈	³⁄₁₆	5.475 ± 0.037	.210 ± 0.005	139.07 ± 0.94	5.33 ± 0.13
-358	5 ⁵⁄₈	6	³⁄₁₆	5.600 ± 0.037	.210 ± 0.005	142.24 ± 0.94	5.33 ± 0.13
-359	5 ³⁄₄	6 ¹⁄₈	³⁄₁₆	5.725 ± 0.037	.210 ± 0.005	145.42 ± 0.94	5.33 ± 0.13
-360	5 ⁷⁄₈	6 ¹⁄₄	³⁄₁₆	5.850 ± 0.037	.210 ± 0.005	148.59 ± 0.94	5.33 ± 0.13
-361	6	6 ³⁄₈	³⁄₁₆	5.975 ± 0.037	.210 ± 0.005	151.77 ± 0.94	5.33 ± 0.13
-362	6 ¹⁄₄	6 ⁵⁄₈	³⁄₁₆	6.225 ± 0.040	.210 ± 0.005	158.12 ± 1.02	5.33 ± 0.13
-363	6 ¹⁄₂	6 ⁷⁄₈	³⁄₁₆	6.475 ± 0.040	.210 ± 0.005	164.47 ± 1.02	5.33 ± 0.13
-364	6 ³⁄₄	7 ¹⁄₈	³⁄₁₆	6.725 ± 0.040	.210 ± 0.005	170.82 ± 1.02	5.33 ± 0.13
-365	7	7 ³⁄₈	³⁄₁₆	6.975 ± 0.040	.210 ± 0.005	177.17 ± 1.02	5.33 ± 0.13
-366	7 ¹⁄₄	7 ⁵⁄₈	³⁄₁₆	7.225 ± 0.045	.210 ± 0.005	183.52 ± 1.14	5.33 ± 0.13
-367	7 ¹⁄₂	7 ⁷⁄₈	³⁄₁₆	7.475 ± 0.045	.210 ± 0.005	189.87 ± 1.14	5.33 ± 0.13
-368	7 ³⁄₄	8 ¹⁄₈	³⁄₁₆	7.725 ± 0.045	.210 ± 0.005	196.22 ± 1.14	5.33 ± 0.13
-369	8	8 ³⁄₈	³⁄₁₆	7.975 ± 0.045	.210 ± 0.005	202.57 ± 1.14	5.33 ± 0.13
-370	8 ¹⁄₄	8 ⁵⁄₈	³⁄₁₆	8.225 ± 0.050	.210 ± 0.005	208.92 ± 1.27	5.33 ± 0.13
-371	8 ¹⁄₂	8 ⁷⁄₈	³⁄₁₆	8.475 ± 0.050	.210 ± 0.005	215.27 ± 1.27	5.33 ± 0.13
-372	8 ³⁄₄	9 ¹⁄₈	³⁄₁₆	8.725 ± 0.050	.210 ± 0.005	221.62 ± 1.27	5.33 ± 0.13
-373	9	9 ³⁄₈	³⁄₁₆	8.975 ± 0.050	.210 ± 0.005	227.97 ± 1.27	5.33 ± 0.13
-374	9 ¹⁄₄	9 ⁵⁄₈	³⁄₁₆	9.225 ± 0.055	.210 ± 0.005	234.32 ± 1.40	5.33 ± 0.13
-375	9 ¹⁄₂	9 ⁷⁄₈	³⁄₁₆	9.475 ± 0.055	.210 ± 0.005	240.67 ± 1.40	5.33 ± 0.13
-376	9 ³⁄₄	10 ¹⁄₈	³⁄₁₆	9.725 ± 0.055	.210 ± 0.005	247.02 ± 1.40	5.33 ± 0.13
-377	10	10 ³⁄₈	³⁄₁₆	9.975 ± 0.055	.210 ± 0.005	253.37 ± 1.40	5.33 ± 0.13
-378	10 ¹⁄₂	10 ⁷⁄₈	³⁄₁₆	10.475 ± 0.060	.210 ± 0.005	266.07 ± 1.52	5.33 ± 0.13
-379	11	11 ³⁄₈	³⁄₁₆	10.975 ± 0.060	.210 ± 0.005	278.77 ± 1.52	5.33 ± 0.13
-380	11 ¹⁄₂	11 ⁷⁄₈	³⁄₁₆	11.475 ± 0.065	.210 ± 0.005	291.47 ± 1.65	5.33 ± 0.13
-381	12	12 ³⁄₈	³⁄₁₆	11.975 ± 0.065	.210 ± 0.005	304.17 ± 1.65	5.33 ± 0.13
-382	13	13 ³⁄₈	³⁄₁₆	12.975 ± 0.065	.210 ± 0.005	329.57 ± 1.65	5.33 ± 0.13
-383	14	14 ³⁄₈	³⁄₁₆	13.975 ± 0.070	.210 ± 0.005	354.97 ± 1.78	5.33 ± 0.13
-384	15	15 ³⁄₈	³⁄₁₆	14.975 ± 0.070	.210 ± 0.005	380.37 ± 1.78	5.33 ± 0.13
-385	16	16 ³⁄₈	³⁄₁₆	15.955 ± 0.075	.210 ± 0.005	405.26 ± 1.91	5.33 ± 0.13
-386	17	17 ³⁄₈	³⁄₁₆	16.955 ± 0.080	.210 ± 0.005	430.66 ± 2.03	5.33 ± 0.13
-387	18	18 ³⁄₈	³⁄₁₆	17.955 ± 0.085	.210 ± 0.005	456.06 ± 2.16	5.33 ± 0.13
-388	19	19 ³⁄₈	³⁄₁₆	18.955 ± 0.090	.210 ± 0.005	481.46 ± 2.29	5.33 ± 0.13
-389	20	20 ³⁄₈	³⁄₁₆	19.955 ± 0.095	.210 ± 0.005	506.86 ± 2.41	5.33 ± 0.13
-390	21	21 ³⁄₈	³⁄₁₆	20.955 ± 0.095	.210 ± 0.005	532.26 ± 2.41	5.33 ± 0.13
-391	22	22 ³⁄₈	³⁄₁₆	21.955 ± 0.100	.210 ± 0.005	557.66 ± 2.54	5.33 ± 0.13
-392	23	23 ³⁄₈	³⁄₁₆	22.940 ± 0.105	.210 ± 0.005	582.68 ± 2.67	5.33 ± 0.13
-393	24	24 ³⁄₈	³⁄₁₆	23.940 ± 0.110	.210 ± 0.005	608.08 ± 2.79	5.33 ± 0.13
-394	25	25 ³⁄₈	³⁄₁₆	24.940 ± 0.115	.210 ± 0.005	633.48 ± 2.92	5.33 ± 0.13
-395	26	26 ³⁄₈	³⁄₁₆	25.940 ± 0.120	.210 ± 0.005	658.88 ± 3.05	5.33 ± 0.13

O-rings with a nominal cross-section of ¹⁄₄ inch (-4##)

Size reference code (dash number)	Nominal size in inches			Decimal size in inches		Decimal size in millimeters
Size reference code (dash number)	ID	OD	Cross-section	ID	Cross-section	ID	Cross-section
-425	4 ¹⁄₂	5	¹⁄₄	4.475 ± 0.033	.275 ± 0.006	113.67 ± 0.84	6.99 ± 0.15
-426	4 ⁵⁄₈	5 ¹⁄₈	¹⁄₄	4.600 ± 0.033	.275 ± 0.006	116.84 ± 0.84	6.99 ± 0.15
-427	4 ³⁄₄	5 ¹⁄₄	¹⁄₄	4.725 ± 0.033	.275 ± 0.006	120.02 ± 0.84	6.99 ± 0.15
-428	4 ⁷⁄₈	5 ³⁄₈	¹⁄₄	4.850 ± 0.033	.275 ± 0.006	123.19 ± 0.84	6.99 ± 0.15
-429	5	5 ¹⁄₂	¹⁄₄	4.975 ± 0.037	.275 ± 0.006	126.37 ± 0.94	6.99 ± 0.15
-430	5 ¹⁄₈	5 ⁵⁄₈	¹⁄₄	5.100 ± 0.037	.275 ± 0.006	129.54 ± 0.94	6.99 ± 0.15
-431	5 ¹⁄₄	5 ³⁄₄	¹⁄₄	5.225 ± 0.037	.275 ± 0.006	132.72 ± 0.94	6.99 ± 0.15
-432	5 ³⁄₈	5 ⁷⁄₈	¹⁄₄	5.350 ± 0.037	.275 ± 0.006	135.89 ± 0.94	6.99 ± 0.15
-433	5 ¹⁄₂	6	¹⁄₄	5.475 ± 0.037	.275 ± 0.006	139.07 ± 0.94	6.99 ± 0.15
-434	5 ⁵⁄₈	6 ¹⁄₈	¹⁄₄	5.600 ± 0.037	.275 ± 0.006	142.24 ± 0.94	6.99 ± 0.15
-435	5 ³⁄₄	6 ¹⁄₄	¹⁄₄	5.725 ± 0.037	.275 ± 0.006	145.42 ± 0.94	6.99 ± 0.15
-436	5 ⁷⁄₈	6 ³⁄₈	¹⁄₄	5.850 ± 0.037	.275 ± 0.006	148.59 ± 0.94	6.99 ± 0.15
-437	6	6 ¹⁄₂	¹⁄₄	5.975 ± 0.037	.275 ± 0.006	151.77 ± 0.94	6.99 ± 0.15
-438	6 ¹⁄₄	6 ³⁄₄	¹⁄₄	6.225 ± 0.040	.275 ± 0.006	158.12 ± 1.02	6.99 ± 0.15
-439	6 ¹⁄₂	7	¹⁄₄	6.475 ± 0.040	.275 ± 0.006	164.47 ± 1.02	6.99 ± 0.15
-440	6 ³⁄₄	7 ¹⁄₄	¹⁄₄	6.725 ± 0.040	.275 ± 0.006	170.82 ± 1.02	6.99 ± 0.15
-441	7	7 ¹⁄₂	¹⁄₄	6.975 ± 0.040	.275 ± 0.006	177.17 ± 1.02	6.99 ± 0.15
-442	7 ¹⁄₄	7 ³⁄₄	¹⁄₄	7.225 ± 0.045	.275 ± 0.006	183.52 ± 1.14	6.99 ± 0.15
-443	7 ¹⁄₂	8	¹⁄₄	7.475 ± 0.045	.275 ± 0.006	189.87 ± 1.14	6.99 ± 0.15
-444	7 ³⁄₄	8 ¹⁄₄	¹⁄₄	7.725 ± 0.045	.275 ± 0.006	196.22 ± 1.14	6.99 ± 0.15
-445	8	8 ¹⁄₂	¹⁄₄	7.975 ± 0.045	.275 ± 0.006	202.57 ± 1.14	6.99 ± 0.15
-446	8 ¹⁄₂	9	¹⁄₄	8.475 ± 0.055	.275 ± 0.006	215.27 ± 1.40	6.99 ± 0.15
-447	9	9 ¹⁄₂	¹⁄₄	8.975 ± 0.055	.275 ± 0.006	227.97 ± 1.40	6.99 ± 0.15
-448	9 ¹⁄₂	10	¹⁄₄	9.475 ± 0.055	.275 ± 0.006	240.67 ± 1.40	6.99 ± 0.15
-449	10	10 ¹⁄₂	¹⁄₄	9.975 ± 0.055	.275 ± 0.006	253.37 ± 1.40	6.99 ± 0.15
-450	10 ¹⁄₂	11	¹⁄₄	10.475 ± 0.060	.275 ± 0.006	266.07 ± 1.52	6.99 ± 0.15
-451	11	11 ¹⁄₂	¹⁄₄	10.975 ± 0.060	.275 ± 0.006	278.77 ± 1.52	6.99 ± 0.15
-452	11 ¹⁄₂	12	¹⁄₄	11.475 ± 0.060	.275 ± 0.006	291.47 ± 1.52	6.99 ± 0.15
-453	12	12 ¹⁄₂	¹⁄₄	11.975 ± 0.060	.275 ± 0.006	304.17 ± 1.52	6.99 ± 0.15
-454	12 ¹⁄₂	13	¹⁄₄	12.475 ± 0.060	.275 ± 0.006	316.87 ± 1.52	6.99 ± 0.15
-455	13	13 ¹⁄₂	¹⁄₄	12.975 ± 0.060	.275 ± 0.006	329.57 ± 1.52	6.99 ± 0.15
-456	13 ¹⁄₂	14	¹⁄₄	13.475 ± 0.070	.275 ± 0.006	342.27 ± 1.78	6.99 ± 0.15
-457	14	14 ¹⁄₂	¹⁄₄	13.975 ± 0.070	.275 ± 0.006	354.97 ± 1.78	6.99 ± 0.15
-458	14 ¹⁄₂	15	¹⁄₄	14.475 ± 0.070	.275 ± 0.006	367.67 ± 1.78	6.99 ± 0.15
-459	15	15 ¹⁄₂	¹⁄₄	14.975 ± 0.070	.275 ± 0.006	380.37 ± 1.78	6.99 ± 0.15
-460	15 ¹⁄₂	16	¹⁄₄	15.475 ± 0.070	.275 ± 0.006	393.07 ± 1.78	6.99 ± 0.15
-461	16	16 ¹⁄₂	¹⁄₄	15.955 ± 0.075	.275 ± 0.006	405.26 ± 1.91	6.99 ± 0.15
-462	16 ¹⁄₂	17	¹⁄₄	16.455 ± 0.075	.275 ± 0.006	417.96 ± 1.91	6.99 ± 0.15
-463	17	17 ¹⁄₂	¹⁄₄	16.955 ± 0.080	.275 ± 0.006	430.66 ± 2.03	6.99 ± 0.15
-464	17 ¹⁄₂	18	¹⁄₄	17.455 ± 0.085	.275 ± 0.006	443.36 ± 2.16	6.99 ± 0.15
-465	18	18 ¹⁄₂	¹⁄₄	17.955 ± 0.085	.275 ± 0.006	456.06 ± 2.16	6.99 ± 0.15
-466	18 ¹⁄₂	19	¹⁄₄	18.455 ± 0.085	.275 ± 0.006	468.76 ± 2.16	6.99 ± 0.15
-467	19	19 ¹⁄₂	¹⁄₄	18.955 ± 0.090	.275 ± 0.006	481.46 ± 2.29	6.99 ± 0.15
-468	19 ¹⁄₂	20	¹⁄₄	19.455 ± 0.090	.275 ± 0.006	494.16 ± 2.29	6.99 ± 0.15
-469	20	20 ¹⁄₂	¹⁄₄	19.955 ± 0.095	.275 ± 0.006	506.86 ± 2.41	6.99 ± 0.15
-470	21	21 ¹⁄₂	¹⁄₄	20.955 ± 0.095	.275 ± 0.006	532.26 ± 2.41	6.99 ± 0.15
-471	22	22 ¹⁄₂	¹⁄₄	21.955 ± 0.100	.275 ± 0.006	557.66 ± 2.54	6.99 ± 0.15
-472	23	23 ¹⁄₂	¹⁄₄	22.940 ± 0.105	.275 ± 0.006	582.68 ± 2.67	6.99 ± 0.15
-473	24	24 ¹⁄₂	¹⁄₄	23.940 ± 0.110	.275 ± 0.006	608.08 ± 2.79	6.99 ± 0.15
-474	25	25 ¹⁄₂	¹⁄₄	24.940 ± 0.115	.275 ± 0.006	633.48 ± 2.92	6.99 ± 0.15
-475	26	26 ¹⁄₂	¹⁄₄	25.940 ± 0.120	.275 ± 0.006	658.88 ± 3.05	6.99 ± 0.15

-9## O-rings

Size reference code (dash number)	Decimal size in inches		Decimal size in millimeters
Size reference code (dash number)	ID	Cross-section	ID	Cross-section
-901	.185 ± 0.005	.056 ± 0.003	4.70 ± 0.13	1.42 ± 0.08
-902	.239 ± 0.005	.064 ± 0.003	6.07 ± 0.13	1.63 ± 0.08
-903	.301 ± 0.005	.064 ± 0.003	7.65 ± 0.13	1.63 ± 0.08
-904	.351 ± 0.005	.072 ± 0.003	8.92 ± 0.13	1.83 ± 0.08
-905	.414 ± 0.005	.072 ± 0.003	10.52 ± 0.13	1.83 ± 0.08
-906	.468 ± 0.005	.078 ± 0.003	11.89 ± 0.13	1.98 ± 0.08
-907	.530 ± 0.007	.082 ± 0.003	13.46 ± 0.18	2.08 ± 0.08
-908	.644 ± 0.009	.087 ± 0.003	16.36 ± 0.23	2.21 ± 0.08
-909	.706 ± 0.009	.097 ± 0.003	17.93 ± 0.23	2.46 ± 0.08
-910	.755 ± 0.009	.097 ± 0.003	19.18 ± 0.23	2.46 ± 0.08
-911	.863 ± 0.009	.116 ± 0.004	21.92 ± 0.23	2.95 ± 0.10
-912	.924 ± 0.009	.116 ± 0.004	23.47 ± 0.23	2.95 ± 0.10
-913	.986 ± 0.010	.116 ± 0.004	25.04 ± 0.25	2.95 ± 0.10
-914	1.047 ± 0.010	.116 ± 0.004	26.59 ± 0.25	2.95 ± 0.10
-916	1.171 ± 0.010	.116 ± 0.004	29.74 ± 0.25	2.95 ± 0.10
-918	1.355 ± 0.012	.116 ± 0.004	34.42 ± 0.30	2.95 ± 0.10
-920	1.475 ± 0.014	.118 ± 0.004	37.47 ± 0.36	3.00 ± 0.10
-924	1.720 ± 0.014	.118 ± 0.004	43.69 ± 0.36	3.00 ± 0.10
-928	2.090 ± 0.018	.118 ± 0.004	53.09 ± 0.46	3.00 ± 0.10
-932	2.338 ± 0.019	.118 ± 0.004	59.37 ± 0.47	3.00 ± 0.10

AS 568 A O-ring standard specifications (inch)

About the AS 568 A standard for O-rings

O-rings with a nominal cross-section of 1⁄32 inch (-001)

O-rings with a nominal cross-section of 3⁄64 inch (-002)

O-rings with a nominal cross-section of 1⁄16 inch (-0##)

O-rings with a nominal cross-section of 3⁄32 inch (-1##)

O-rings with a nominal cross-section of 1⁄8 inch (-2##)

O-rings with a nominal cross-section of 3⁄16 inch (-3##)

O-rings with a nominal cross-section of 1⁄4 inch (-4##)