Reference · 374 dash numbers · 349 of them AS568B standard sizes

AS568 O-ring size chart

Every dash number in SAE AS568B (aerospace size standard for O-rings), with inside diameter, cross section and outside diameter in inches and millimetres and the published tolerance on each. Pick a dash number for the full page.

How to read a dash number

A dash number is not a diameter. The series it sits in fixes the cross section - the thickness of the cord - and the position within the series sets the inside diameter. So every 2xx size shares one cross section and differs only in bore, which is why a seal that leaks is so often the right inside diameter in the wrong series. The fractional names are nicknames rather than dimensions: the 1xx cord is called 3/32 and measures 0.103 inches.

Outside diameter is a sum, not a published figure

Outside diameter is not a published AS568 dimension. The standard fixes the inside diameter and the cross section, and the outside diameter follows from them: OD = ID + 2 x CS. Every outside diameter on this site is that sum, not a figure read from a table, and it inherits both tolerances rather than carrying one of its own.

What is here, and what is not

This chart carries the five cross-section series - 0xx, 1xx, 2xx, 3xx and 4xx. It does NOT carry the 900 series, the 20 straight-thread boss gaskets AS568 also lists: those are boss seals rather than O-rings in the usual sense and are sized to the fitting, so they are left out rather than mixed in. Dash numbers -400 to -424 are carried and flagged: two of the four catalogues list them under AS568, and the AS568B list of 369 standard sizes does not.

Of the 374 dash numbers listed, 349 are AS568B standard sizes and 25 are the catalogued -400 to -424 block, marked as such on every page they appear. Every dimension was read from at least two independent published tables before it was printed.

50 sizes · cross section 0.070" (1.78 mm) ±0.003"

0xx series

Pneumatic, instrumentation and small seals. Standard dash numbers 004 to 050. -001, -002, -003 carry a smaller cross section than the rest of the series.

AS568 0xx series dash numbers with inside diameter, cross section and outside diameter.
DashID (in)CS (in)OD (in)ID (mm)AS568B
AS568-0010.0290.0400.1090.74yes
AS568-0020.0420.0500.1421.07yes
AS568-0030.0560.0600.1761.42yes
AS568-0040.0700.0700.2101.78yes
AS568-0050.1010.0700.2412.57yes
AS568-0060.1140.0700.2542.90yes
AS568-0070.1450.0700.2853.68yes
AS568-0080.1760.0700.3164.47yes
AS568-0090.2080.0700.3485.28yes
AS568-0100.2390.0700.3796.07yes
AS568-0110.3010.0700.4417.65yes
AS568-0120.3640.0700.5049.25yes
AS568-0130.4260.0700.56610.82yes
AS568-0140.4890.0700.62912.42yes
AS568-0150.5510.0700.69114.00yes
AS568-0160.6140.0700.75415.60yes
AS568-0170.6760.0700.81617.17yes
AS568-0180.7390.0700.87918.77yes
AS568-0190.8010.0700.94120.35yes
AS568-0200.8640.0701.00421.95yes
AS568-0210.9260.0701.06623.52yes
AS568-0220.9890.0701.12925.12yes
AS568-0231.0510.0701.19126.70yes
AS568-0241.1140.0701.25428.30yes
AS568-0251.1760.0701.31629.87yes
AS568-0261.2390.0701.37931.47yes
AS568-0271.3010.0701.44133.05yes
AS568-0281.3640.0701.50434.65yes
AS568-0291.4890.0701.62937.82yes
AS568-0301.6140.0701.75441.00yes
AS568-0311.7390.0701.87944.17yes
AS568-0321.8640.0702.00447.35yes
AS568-0331.9890.0702.12950.52yes
AS568-0342.1140.0702.25453.70yes
AS568-0352.2390.0702.37956.87yes
AS568-0362.3640.0702.50460.05yes
AS568-0372.4890.0702.62963.22yes
AS568-0382.6140.0702.75466.40yes
AS568-0392.7390.0702.87969.57yes
AS568-0402.8640.0703.00472.75yes
AS568-0412.9890.0703.12975.92yes
AS568-0423.2390.0703.37982.27yes
AS568-0433.4890.0703.62988.62yes
AS568-0443.7390.0703.87994.97yes
AS568-0453.9890.0704.129101.32yes
AS568-0464.2390.0704.379107.67yes
AS568-0474.4890.0704.629114.02yes
AS568-0484.7390.0704.879120.37yes
AS568-0494.9890.0705.129126.72yes
AS568-0505.2390.0705.379133.07yes

77 sizes · cross section 0.103" (2.62 mm) ±0.003"

1xx series

Hydraulic, pump and valve. Standard dash numbers 102 to 178.

AS568 1xx series dash numbers with inside diameter, cross section and outside diameter.
DashID (in)CS (in)OD (in)ID (mm)AS568B
AS568-1020.0490.1030.2551.24yes
AS568-1030.0810.1030.2872.06yes
AS568-1040.1120.1030.3182.84yes
AS568-1050.1430.1030.3493.63yes
AS568-1060.1740.1030.3804.42yes
AS568-1070.2060.1030.4125.23yes
AS568-1080.2370.1030.4436.02yes
AS568-1090.2990.1030.5057.59yes
AS568-1100.3620.1030.5689.19yes
AS568-1110.4240.1030.63010.77yes
AS568-1120.4870.1030.69312.37yes
AS568-1130.5490.1030.75513.94yes
AS568-1140.6120.1030.81815.54yes
AS568-1150.6740.1030.88017.12yes
AS568-1160.7370.1030.94318.72yes
AS568-1170.7990.1031.00520.29yes
AS568-1180.8620.1031.06821.89yes
AS568-1190.9240.1031.13023.47yes
AS568-1200.9870.1031.19325.07yes
AS568-1211.0490.1031.25526.64yes
AS568-1221.1120.1031.31828.24yes
AS568-1231.1740.1031.38029.82yes
AS568-1241.2370.1031.44331.42yes
AS568-1251.2990.1031.50532.99yes
AS568-1261.3620.1031.56834.59yes
AS568-1271.4240.1031.63036.17yes
AS568-1281.4870.1031.69337.77yes
AS568-1291.5490.1031.75539.34yes
AS568-1301.6120.1031.81840.94yes
AS568-1311.6740.1031.88042.52yes
AS568-1321.7370.1031.94344.12yes
AS568-1331.7990.1032.00545.69yes
AS568-1341.8620.1032.06847.29yes
AS568-1351.9250.1032.13148.90yes
AS568-1361.9870.1032.19350.47yes
AS568-1372.0500.1032.25652.07yes
AS568-1382.1120.1032.31853.64yes
AS568-1392.1750.1032.38155.25yes
AS568-1402.2370.1032.44356.82yes
AS568-1412.3000.1032.50658.42yes
AS568-1422.3620.1032.56859.99yes
AS568-1432.4250.1032.63161.60yes
AS568-1442.4870.1032.69363.17yes
AS568-1452.5500.1032.75664.77yes
AS568-1462.6120.1032.81866.34yes
AS568-1472.6750.1032.88167.95yes
AS568-1482.7370.1032.94369.52yes
AS568-1492.8000.1033.00671.12yes
AS568-1502.8620.1033.06872.69yes
AS568-1512.9870.1033.19375.87yes
AS568-1523.2370.1033.44382.22yes
AS568-1533.4870.1033.69388.57yes
AS568-1543.7370.1033.94394.92yes
AS568-1553.9870.1034.193101.27yes
AS568-1564.2370.1034.443107.62yes
AS568-1574.4870.1034.693113.97yes
AS568-1584.7370.1034.943120.32yes
AS568-1594.9870.1035.193126.67yes
AS568-1605.2370.1035.443133.02yes
AS568-1615.4870.1035.693139.37yes
AS568-1625.7370.1035.943145.72yes
AS568-1635.9870.1036.193152.07yes
AS568-1646.2370.1036.443158.42yes
AS568-1656.4870.1036.693164.77yes
AS568-1666.7370.1036.943171.12yes
AS568-1676.9870.1037.193177.47yes
AS568-1687.2370.1037.443183.82yes
AS568-1697.4870.1037.693190.17yes
AS568-1707.7370.1037.943196.52yes
AS568-1717.9870.1038.193202.87yes
AS568-1728.2370.1038.443209.22yes
AS568-1738.4870.1038.693215.57yes
AS568-1748.7370.1038.943221.92yes
AS568-1758.9870.1039.193228.27yes
AS568-1769.2370.1039.443234.62yes
AS568-1779.4870.1039.693240.97yes
AS568-1789.7370.1039.943247.32yes

84 sizes · cross section 0.139" (3.53 mm) ±0.004"

2xx series

General purpose and cylinders. Standard dash numbers 201 to 284.

AS568 2xx series dash numbers with inside diameter, cross section and outside diameter.
DashID (in)CS (in)OD (in)ID (mm)AS568B
AS568-2010.1710.1390.4494.34yes
AS568-2020.2340.1390.5125.94yes
AS568-2030.2960.1390.5747.52yes
AS568-2040.3590.1390.6379.12yes
AS568-2050.4210.1390.69910.69yes
AS568-2060.4840.1390.76212.29yes
AS568-2070.5460.1390.82413.87yes
AS568-2080.6090.1390.88715.47yes
AS568-2090.6710.1390.94917.04yes
AS568-2100.7340.1391.01218.64yes
AS568-2110.7960.1391.07420.22yes
AS568-2120.8590.1391.13721.82yes
AS568-2130.9210.1391.19923.39yes
AS568-2140.9840.1391.26224.99yes
AS568-2151.0460.1391.32426.57yes
AS568-2161.1090.1391.38728.17yes
AS568-2171.1710.1391.44929.74yes
AS568-2181.2340.1391.51231.34yes
AS568-2191.2960.1391.57432.92yes
AS568-2201.3590.1391.63734.52yes
AS568-2211.4210.1391.69936.09yes
AS568-2221.4840.1391.76237.69yes
AS568-2231.6090.1391.88740.87yes
AS568-2241.7340.1392.01244.04yes
AS568-2251.8590.1392.13747.22yes
AS568-2261.9840.1392.26250.39yes
AS568-2272.1090.1392.38753.57yes
AS568-2282.2340.1392.51256.74yes
AS568-2292.3590.1392.63759.92yes
AS568-2302.4840.1392.76263.09yes
AS568-2312.6090.1392.88766.27yes
AS568-2322.7340.1393.01269.44yes
AS568-2332.8590.1393.13772.62yes
AS568-2342.9840.1393.26275.79yes
AS568-2353.1090.1393.38778.97yes
AS568-2363.2340.1393.51282.14yes
AS568-2373.3590.1393.63785.32yes
AS568-2383.4840.1393.76288.49yes
AS568-2393.6090.1393.88791.67yes
AS568-2403.7340.1394.01294.84yes
AS568-2413.8590.1394.13798.02yes
AS568-2423.9840.1394.262101.19yes
AS568-2434.1090.1394.387104.37yes
AS568-2444.2340.1394.512107.54yes
AS568-2454.3590.1394.637110.72yes
AS568-2464.4840.1394.762113.89yes
AS568-2474.6090.1394.887117.07yes
AS568-2484.7340.1395.012120.24yes
AS568-2494.8590.1395.137123.42yes
AS568-2504.9840.1395.262126.59yes
AS568-2515.1090.1395.387129.77yes
AS568-2525.2340.1395.512132.94yes
AS568-2535.3590.1395.637136.12yes
AS568-2545.4840.1395.762139.29yes
AS568-2555.6090.1395.887142.47yes
AS568-2565.7340.1396.012145.64yes
AS568-2575.8590.1396.137148.82yes
AS568-2585.9840.1396.262151.99yes
AS568-2596.2340.1396.512158.34yes
AS568-2606.4840.1396.762164.69yes
AS568-2616.7340.1397.012171.04yes
AS568-2626.9840.1397.262177.39yes
AS568-2637.2340.1397.512183.74yes
AS568-2647.4840.1397.762190.09yes
AS568-2657.7340.1398.012196.44yes
AS568-2667.9840.1398.262202.79yes
AS568-2678.2340.1398.512209.14yes
AS568-2688.4840.1398.762215.49yes
AS568-2698.7340.1399.012221.84yes
AS568-2708.9840.1399.262228.19yes
AS568-2719.2340.1399.512234.54yes
AS568-2729.4840.1399.762240.89yes
AS568-2739.7340.13910.012247.24yes
AS568-2749.9840.13910.262253.59yes
AS568-27510.4840.13910.762266.29yes
AS568-27610.9840.13911.262278.99yes
AS568-27711.4840.13911.762291.69yes
AS568-27811.9840.13912.262304.39yes
AS568-27912.9840.13913.262329.79yes
AS568-28013.9840.13914.262355.19yes
AS568-28114.9840.13915.262380.59yes
AS568-28215.9550.13916.233405.26yes
AS568-28316.9550.13917.233430.66yes
AS568-28417.9550.13918.233456.06yes

87 sizes · cross section 0.210" (5.33 mm) ±0.005"

3xx series

Heavy hydraulic and high pressure. Standard dash numbers 309 to 395.

AS568 3xx series dash numbers with inside diameter, cross section and outside diameter.
DashID (in)CS (in)OD (in)ID (mm)AS568B
AS568-3090.4120.2100.83210.46yes
AS568-3100.4750.2100.89512.07yes
AS568-3110.5370.2100.95713.64yes
AS568-3120.6000.2101.02015.24yes
AS568-3130.6620.2101.08216.81yes
AS568-3140.7250.2101.14518.42yes
AS568-3150.7870.2101.20719.99yes
AS568-3160.8500.2101.27021.59yes
AS568-3170.9120.2101.33223.16yes
AS568-3180.9750.2101.39524.77yes
AS568-3191.0370.2101.45726.34yes
AS568-3201.1000.2101.52027.94yes
AS568-3211.1620.2101.58229.51yes
AS568-3221.2250.2101.64531.12yes
AS568-3231.2870.2101.70732.69yes
AS568-3241.3500.2101.77034.29yes
AS568-3251.4750.2101.89537.47yes
AS568-3261.6000.2102.02040.64yes
AS568-3271.7250.2102.14543.82yes
AS568-3281.8500.2102.27046.99yes
AS568-3291.9750.2102.39550.17yes
AS568-3302.1000.2102.52053.34yes
AS568-3312.2250.2102.64556.52yes
AS568-3322.3500.2102.77059.69yes
AS568-3332.4750.2102.89562.87yes
AS568-3342.6000.2103.02066.04yes
AS568-3352.7250.2103.14569.22yes
AS568-3362.8500.2103.27072.39yes
AS568-3372.9750.2103.39575.57yes
AS568-3383.1000.2103.52078.74yes
AS568-3393.2250.2103.64581.92yes
AS568-3403.3500.2103.77085.09yes
AS568-3413.4750.2103.89588.27yes
AS568-3423.6000.2104.02091.44yes
AS568-3433.7250.2104.14594.62yes
AS568-3443.8500.2104.27097.79yes
AS568-3453.9750.2104.395100.97yes
AS568-3464.1000.2104.520104.14yes
AS568-3474.2250.2104.645107.32yes
AS568-3484.3500.2104.770110.49yes
AS568-3494.4750.2104.895113.67yes
AS568-3504.6000.2105.020116.84yes
AS568-3514.7250.2105.145120.02yes
AS568-3524.8500.2105.270123.19yes
AS568-3534.9750.2105.395126.37yes
AS568-3545.1000.2105.520129.54yes
AS568-3555.2250.2105.645132.72yes
AS568-3565.3500.2105.770135.89yes
AS568-3575.4750.2105.895139.07yes
AS568-3585.6000.2106.020142.24yes
AS568-3595.7250.2106.145145.42yes
AS568-3605.8500.2106.270148.59yes
AS568-3615.9750.2106.395151.77yes
AS568-3626.2250.2106.645158.12yes
AS568-3636.4750.2106.895164.47yes
AS568-3646.7250.2107.145170.82yes
AS568-3656.9750.2107.395177.17yes
AS568-3667.2250.2107.645183.52yes
AS568-3677.4750.2107.895189.87yes
AS568-3687.7250.2108.145196.22yes
AS568-3697.9750.2108.395202.57yes
AS568-3708.2250.2108.645208.92yes
AS568-3718.4750.2108.895215.27yes
AS568-3728.7250.2109.145221.62yes
AS568-3738.9750.2109.395227.97yes
AS568-3749.2250.2109.645234.32yes
AS568-3759.4750.2109.895240.67yes
AS568-3769.7250.21010.145247.02yes
AS568-3779.9750.21010.395253.37yes
AS568-37810.4750.21010.895266.07yes
AS568-37910.9750.21011.395278.77yes
AS568-38011.4750.21011.895291.47yes
AS568-38111.9750.21012.395304.17yes
AS568-38212.9750.21013.395329.57yes
AS568-38313.9750.21014.395354.97yes
AS568-38414.9750.21015.395380.37yes
AS568-38515.9550.21016.375405.26yes
AS568-38616.9550.21017.375430.66yes
AS568-38717.9550.21018.375456.06yes
AS568-38818.9550.21019.375481.46yes
AS568-38919.9550.21020.375506.86yes
AS568-39020.9550.21021.375532.26yes
AS568-39121.9550.21022.375557.66yes
AS568-39222.9400.21023.360582.68yes
AS568-39323.9400.21024.360608.08yes
AS568-39424.9400.21025.360633.48yes
AS568-39525.9400.21026.360658.88yes

76 sizes · cross section 0.275" (6.99 mm) ±0.006"

4xx series

Industrial flange and piping. Standard dash numbers 425 to 475.

AS568 4xx series dash numbers with inside diameter, cross section and outside diameter.
DashID (in)CS (in)OD (in)ID (mm)AS568B
AS568-4001.3500.2751.90034.29catalogue size
AS568-4011.4750.2752.02537.47catalogue size
AS568-4021.6000.2752.15040.64catalogue size
AS568-4031.7250.2752.27543.82catalogue size
AS568-4041.8500.2752.40046.99catalogue size
AS568-4051.9750.2752.52550.17catalogue size
AS568-4062.1000.2752.65053.34catalogue size
AS568-4072.2250.2752.77556.52catalogue size
AS568-4082.3500.2752.90059.69catalogue size
AS568-4092.4750.2753.02562.87catalogue size
AS568-4102.6000.2753.15066.04catalogue size
AS568-4112.7250.2753.27569.22catalogue size
AS568-4122.8500.2753.40072.39catalogue size
AS568-4132.9750.2753.52575.57catalogue size
AS568-4143.1000.2753.65078.74catalogue size
AS568-4153.2250.2753.77581.92catalogue size
AS568-4163.3500.2753.90085.09catalogue size
AS568-4173.4750.2754.02588.27catalogue size
AS568-4183.6000.2754.15091.44catalogue size
AS568-4193.7250.2754.27594.62catalogue size
AS568-4203.8500.2754.40097.79catalogue size
AS568-4213.9750.2754.525100.97catalogue size
AS568-4224.1000.2754.650104.14catalogue size
AS568-4234.2250.2754.775107.32catalogue size
AS568-4244.3500.2754.900110.49catalogue size
AS568-4254.4750.2755.025113.67yes
AS568-4264.6000.2755.150116.84yes
AS568-4274.7250.2755.275120.02yes
AS568-4284.8500.2755.400123.19yes
AS568-4294.9750.2755.525126.37yes
AS568-4305.1000.2755.650129.54yes
AS568-4315.2250.2755.775132.72yes
AS568-4325.3500.2755.900135.89yes
AS568-4335.4750.2756.025139.07yes
AS568-4345.6000.2756.150142.24yes
AS568-4355.7250.2756.275145.42yes
AS568-4365.8500.2756.400148.59yes
AS568-4375.9750.2756.525151.77yes
AS568-4386.2250.2756.775158.12yes
AS568-4396.4750.2757.025164.47yes
AS568-4406.7250.2757.275170.82yes
AS568-4416.9750.2757.525177.17yes
AS568-4427.2250.2757.775183.52yes
AS568-4437.4750.2758.025189.87yes
AS568-4447.7250.2758.275196.22yes
AS568-4457.9750.2758.525202.57yes
AS568-4468.4750.2759.025215.27yes
AS568-4478.9750.2759.525227.97yes
AS568-4489.4750.27510.025240.67yes
AS568-4499.9750.27510.525253.37yes
AS568-45010.4750.27511.025266.07yes
AS568-45110.9750.27511.525278.77yes
AS568-45211.4750.27512.025291.47yes
AS568-45311.9750.27512.525304.17yes
AS568-45412.4750.27513.025316.87yes
AS568-45512.9750.27513.525329.57yes
AS568-45613.4750.27514.025342.27yes
AS568-45713.9750.27514.525354.97yes
AS568-45814.4750.27515.025367.67yes
AS568-45914.9750.27515.525380.37yes
AS568-46015.4750.27516.025393.07yes
AS568-46115.9550.27516.505405.26yes
AS568-46216.4550.27517.005417.96yes
AS568-46316.9550.27517.505430.66yes
AS568-46417.4550.27518.005443.36yes
AS568-46517.9550.27518.505456.06yes
AS568-46618.4550.27519.005468.76yes
AS568-46718.9550.27519.505481.46yes
AS568-46819.4550.27520.005494.16yes
AS568-46919.9550.27520.505506.86yes
AS568-47020.9550.27521.505532.26yes
AS568-47121.9550.27522.505557.66yes
AS568-47222.9400.27523.490582.68yes
AS568-47323.9400.27524.490608.08yes
AS568-47424.9400.27525.490633.48yes
AS568-47525.9400.27526.490658.88yes