Metric size list, ISO 3601-1
ISO 3601-1 metric O-ring sizes, groups A to E
An ISO 3601-1 metric O-ring is written as a group letter and four digits: the letter is the cross-section group and the digits give the inside diameter to the nearest tenth of a millimeter, so C0250 is 25.0 mm by 3.55 mm. This page lists the 358 metric sizes in the five groups, from 1.8 mm to 400.0 mm inside diameter, each with its inch conversion, its code and the nearest AS568 size, not an equivalent; the print governs. The metric cords are 1.80, 2.65, 3.55, 5.30 and 7.00 mm. An AS568 inch size in millimeters is a different list, on the AS568 size chart. Send the code or the ID x cross-section from your print and we quote it in the compound you name.
- Sizes listed
- 358five cross-section groups
- Cross-sections
- 1.80 to 7.00 mmgroups A to E
- Inside diameters
- 1.8 to 400.0 mm0.071 to 15.748 in
- Code
- C0250group + ID to the nearest 0.1 mm
Where the figures come from
Every size, cross-section and tolerance on this page is read from Precision Polymer Engineering, 'ISO 3601 O-ring Sizes' reference table (read 2026-09-06). Every row is checked here: the code matches the inside diameter to the nearest tenth of a millimeter, the cross-section matches its group, and the inch and millimeter values agree. The ISO 3601 documents themselves were not used, and no standard's text or table is reproduced. The arrangement below, with the nearest AS568 size beside each metric size, is our own. The AS568 figures are this site's AS568 size chart.
The five cross-section groups
Group A is the 1.80 mm (0.071 in) cord, +/- 0.08 mm:76 sizes from 1.8 to 125.0 mm inside diameter, with ID tolerances from +/- 0.13 to +/- 0.81 mm. Group B is the 2.65 mm (0.104 in) cord, +/- 0.09 mm:82 sizes from 4.5 to 250.0 mm inside diameter, with ID tolerances from +/- 0.13 to +/- 1.49 mm. Group C is the 3.55 mm (0.140 in) cord, +/- 0.10 mm:95 sizes from 14.0 to 355.0 mm inside diameter, with ID tolerances from +/- 0.18 to +/- 2.06 mm. Group D is the 5.30 mm (0.209 in) cord, +/- 0.13 mm:59 sizes from 37.5 to 200.0 mm inside diameter, with ID tolerances from +/- 0.32 to +/- 1.22 mm. Group E is the 7.00 mm (0.276 in) cord, +/- 0.15 mm:46 sizes from 109.0 to 400.0 mm inside diameter, with ID tolerances from +/- 0.72 to +/- 2.29 mm.
Beside each metric size the lists name the nearest AS568 size, not an equivalent; the print governs. It is the AS568 dash with the closest inside diameter in the series whose cord sits next to the group's, and the difference is AS568 ID minus metric ID. It is a reading of two lists, never a recommendation: the two cords and their tolerances differ, and a gland drawn for one list is not drawn for the other.
Inch values are converted from millimeters. The tolerance class your print names governs.
Group A sizes, 1.80 mm (0.071 in) cross-section
| ID mm | ID in | ISO code | Nearest AS568 size, not an equivalent; the print governs | ID difference mm |
|---|---|---|---|---|
| 1.80 | 0.071 | A0018 | -004 | -0.02 |
| 2.00 | 0.079 | A0020 | -004 | -0.22 |
| 2.50 | 0.098 | A0025 | -005 | +0.07 |
| 2.80 | 0.110 | A0028 | -006 | +0.10 |
| 3.15 | 0.124 | A0032 | -006 | -0.25 |
| 3.55 | 0.140 | A0036 | -007 | +0.13 |
| 3.75 | 0.148 | A0038 | -007 | -0.07 |
| 4.00 | 0.157 | A0040 | -007 | -0.32 |
| 4.50 | 0.177 | A0045 | -008 | -0.03 |
| 4.87 | 0.192 | A0049 | -008 | -0.40 |
| 5.00 | 0.197 | A0050 | -009 | +0.28 |
| 5.15 | 0.203 | A0052 | -009 | +0.13 |
| 5.30 | 0.209 | A0053 | -009 | -0.02 |
| 5.60 | 0.220 | A0056 | -009 | -0.32 |
| 6.00 | 0.236 | A0060 | -010 | +0.07 |
| 6.30 | 0.248 | A0063 | -010 | -0.23 |
| 6.70 | 0.264 | A0067 | -010 | -0.63 |
| 6.90 | 0.272 | A0069 | -011 | +0.75 |
| 7.10 | 0.280 | A0071 | -011 | +0.55 |
| 7.50 | 0.295 | A0075 | -011 | +0.15 |
| 8.00 | 0.315 | A0080 | -011 | -0.35 |
| 8.50 | 0.335 | A0085 | -012 | +0.75 |
| 8.75 | 0.344 | A0088 | -012 | +0.50 |
| 9.00 | 0.354 | A0090 | -012 | +0.25 |
| 9.50 | 0.374 | A0095 | -012 | -0.25 |
| 10.00 | 0.394 | A0100 | -012 | -0.75 |
| 10.60 | 0.417 | A0106 | -013 | +0.22 |
| 11.20 | 0.441 | A0112 | -013 | -0.38 |
| 11.80 | 0.465 | A0118 | -014 | +0.62 |
| 12.50 | 0.492 | A0125 | -014 | -0.08 |
| 13.20 | 0.520 | A0132 | -014 | -0.78 |
| 14.00 | 0.551 | A0140 | -015 | 0.00 |
| 15.00 | 0.591 | A0150 | -016 | +0.60 |
| 16.00 | 0.630 | A0160 | -016 | -0.40 |
| 17.00 | 0.669 | A0170 | -017 | +0.17 |
| 18.00 | 0.709 | A0180 | -018 | +0.77 |
| 19.00 | 0.748 | A0190 | -018 | -0.23 |
| 20.00 | 0.787 | A0200 | -019 | +0.35 |
| 21.20 | 0.835 | A0212 | -020 | +0.75 |
| 22.40 | 0.882 | A0224 | -020 | -0.45 |
| 23.60 | 0.929 | A0236 | -021 | -0.08 |
| 25.00 | 0.984 | A0250 | -022 | +0.12 |
| 25.80 | 1.016 | A0258 | -022 | -0.68 |
| 26.50 | 1.043 | A0265 | -023 | +0.20 |
| 28.00 | 1.102 | A0280 | -024 | +0.30 |
| 30.00 | 1.181 | A0300 | -025 | -0.13 |
| 31.50 | 1.240 | A0315 | -026 | -0.03 |
| 32.50 | 1.280 | A0325 | -027 | +0.55 |
| 33.50 | 1.319 | A0335 | -027 | -0.45 |
| 34.50 | 1.358 | A0345 | -028 | +0.15 |
| 35.50 | 1.398 | A0355 | -028 | -0.85 |
| 36.50 | 1.437 | A0365 | -029 | +1.32 |
| 37.50 | 1.476 | A0375 | -029 | +0.32 |
| 40.00 | 1.575 | A0400 | -030 | +1.00 |
| 41.20 | 1.622 | A0412 | -030 | -0.20 |
| 42.50 | 1.673 | A0425 | -030 | -1.50 |
| 43.70 | 1.720 | A0437 | -031 | +0.47 |
| 45.00 | 1.772 | A0450 | -031 | -0.83 |
| 47.50 | 1.870 | A0475 | -032 | -0.15 |
| 50.00 | 1.969 | A0500 | -033 | +0.52 |
| 53.00 | 2.087 | A0530 | -034 | +0.70 |
| 56.00 | 2.205 | A0560 | -035 | +0.87 |
| 60.00 | 2.362 | A0600 | -036 | +0.05 |
| 63.00 | 2.480 | A0630 | -037 | +0.22 |
| 67.00 | 2.638 | A0670 | -038 | -0.60 |
| 71.00 | 2.795 | A0710 | -039 | -1.43 |
| 75.00 | 2.953 | A0750 | -041 | +0.92 |
| 80.00 | 3.150 | A0800 | -042 | +2.27 |
| 85.00 | 3.346 | A0850 | -042 | -2.73 |
| 90.00 | 3.543 | A0900 | -043 | -1.38 |
| 95.00 | 3.740 | A0950 | -044 | -0.03 |
| 100.00 | 3.937 | A1000 | -045 | +1.32 |
| 106.00 | 4.173 | A1060 | -046 | +1.67 |
| 112.00 | 4.409 | A1120 | -047 | +2.02 |
| 118.00 | 4.646 | A1180 | -048 | +2.37 |
| 125.00 | 4.921 | A1250 | -049 | +1.72 |
Group B sizes, 2.65 mm (0.104 in) cross-section
| ID mm | ID in | ISO code | Nearest AS568 size, not an equivalent; the print governs | ID difference mm |
|---|---|---|---|---|
| 4.50 | 0.177 | B0045 | -106 | -0.08 |
| 5.30 | 0.209 | B0053 | -107 | -0.07 |
| 6.00 | 0.236 | B0060 | -108 | +0.02 |
| 6.90 | 0.272 | B0069 | -109 | +0.69 |
| 8.00 | 0.315 | B0080 | -109 | -0.41 |
| 9.00 | 0.354 | B0090 | -110 | +0.19 |
| 9.50 | 0.374 | B0095 | -110 | -0.31 |
| 10.00 | 0.394 | B0100 | -111 | +0.77 |
| 10.60 | 0.417 | B0106 | -111 | +0.17 |
| 11.20 | 0.441 | B0112 | -111 | -0.43 |
| 11.80 | 0.465 | B0118 | -112 | +0.57 |
| 12.50 | 0.492 | B0125 | -112 | -0.13 |
| 13.20 | 0.520 | B0132 | -113 | +0.74 |
| 14.00 | 0.551 | B0140 | -113 | -0.06 |
| 15.00 | 0.591 | B0150 | -114 | +0.54 |
| 16.00 | 0.630 | B0160 | -114 | -0.46 |
| 17.00 | 0.669 | B0170 | -115 | +0.12 |
| 18.00 | 0.709 | B0180 | -116 | +0.72 |
| 19.00 | 0.748 | B0190 | -116 | -0.28 |
| 20.00 | 0.787 | B0200 | -117 | +0.29 |
| 21.20 | 0.835 | B0212 | -118 | +0.69 |
| 22.40 | 0.882 | B0224 | -118 | -0.51 |
| 23.60 | 0.929 | B0236 | -119 | -0.13 |
| 25.00 | 0.984 | B0250 | -120 | +0.07 |
| 25.80 | 1.016 | B0258 | -120 | -0.73 |
| 26.50 | 1.043 | B0265 | -121 | +0.14 |
| 28.00 | 1.102 | B0280 | -122 | +0.24 |
| 30.00 | 1.181 | B0300 | -123 | -0.18 |
| 31.50 | 1.240 | B0315 | -124 | -0.08 |
| 32.50 | 1.280 | B0325 | -125 | +0.49 |
| 33.50 | 1.319 | B0335 | -125 | -0.51 |
| 34.50 | 1.358 | B0345 | -126 | +0.09 |
| 35.50 | 1.398 | B0355 | -127 | +0.67 |
| 36.50 | 1.437 | B0365 | -127 | -0.33 |
| 37.50 | 1.476 | B0375 | -128 | +0.27 |
| 38.70 | 1.524 | B0387 | -129 | +0.64 |
| 40.00 | 1.575 | B0400 | -129 | -0.66 |
| 41.20 | 1.622 | B0412 | -130 | -0.26 |
| 42.50 | 1.673 | B0425 | -131 | +0.02 |
| 43.70 | 1.720 | B0437 | -132 | +0.42 |
| 45.00 | 1.772 | B0450 | -133 | +0.69 |
| 46.20 | 1.819 | B0462 | -133 | -0.51 |
| 47.50 | 1.870 | B0475 | -134 | -0.21 |
| 48.70 | 1.917 | B0487 | -135 | +0.20 |
| 50.00 | 1.969 | B0500 | -136 | +0.47 |
| 51.50 | 2.028 | B0515 | -137 | +0.57 |
| 53.00 | 2.087 | B0530 | -138 | +0.64 |
| 54.50 | 2.146 | B0545 | -139 | +0.75 |
| 56.00 | 2.205 | B0560 | -139 | -0.75 |
| 58.00 | 2.283 | B0580 | -141 | +0.42 |
| 60.00 | 2.362 | B0600 | -142 | -0.01 |
| 61.50 | 2.421 | B0615 | -143 | +0.10 |
| 63.00 | 2.480 | B0630 | -144 | +0.17 |
| 65.00 | 2.559 | B0650 | -145 | -0.23 |
| 67.00 | 2.638 | B0670 | -146 | -0.66 |
| 69.00 | 2.717 | B0690 | -148 | +0.52 |
| 71.00 | 2.795 | B0710 | -149 | +0.12 |
| 73.00 | 2.874 | B0730 | -150 | -0.31 |
| 75.00 | 2.953 | B0750 | -151 | +0.87 |
| 80.00 | 3.150 | B0800 | -152 | +2.22 |
| 85.00 | 3.346 | B0850 | -152 | -2.78 |
| 90.00 | 3.543 | B0900 | -153 | -1.43 |
| 95.00 | 3.740 | B0950 | -154 | -0.08 |
| 100.00 | 3.937 | B1000 | -155 | +1.27 |
| 106.00 | 4.173 | B1060 | -156 | +1.62 |
| 112.00 | 4.409 | B1120 | -157 | +1.97 |
| 118.00 | 4.646 | B1180 | -158 | +2.32 |
| 125.00 | 4.921 | B1250 | -159 | +1.67 |
| 132.00 | 5.197 | B1320 | -160 | +1.02 |
| 140.00 | 5.512 | B1400 | -161 | -0.63 |
| 150.00 | 5.906 | B1500 | -163 | +2.07 |
| 160.00 | 6.299 | B1600 | -164 | -1.58 |
| 170.00 | 6.693 | B1700 | -166 | +1.12 |
| 180.00 | 7.087 | B1800 | -167 | -2.53 |
| 190.00 | 7.480 | B1900 | -169 | +0.17 |
| 200.00 | 7.874 | B2000 | -171 | +2.87 |
| 212.00 | 8.346 | B2120 | -172 | -2.78 |
| 224.00 | 8.819 | B2240 | -174 | -2.08 |
| 230.00 | 9.055 | B2300 | -175 | -1.73 |
| 236.00 | 9.291 | B2360 | -176 | -1.38 |
| 243.00 | 9.567 | B2430 | -177 | -2.03 |
| 250.00 | 9.843 | B2500 | -178 | -2.68 |
Group C sizes, 3.55 mm (0.140 in) cross-section
| ID mm | ID in | ISO code | Nearest AS568 size, not an equivalent; the print governs | ID difference mm |
|---|---|---|---|---|
| 14.00 | 0.551 | C0140 | -207 | -0.13 |
| 15.00 | 0.591 | C0150 | -208 | +0.47 |
| 16.00 | 0.630 | C0160 | -208 | -0.53 |
| 17.00 | 0.669 | C0170 | -209 | +0.04 |
| 18.00 | 0.709 | C0180 | -210 | +0.64 |
| 19.00 | 0.748 | C0190 | -210 | -0.36 |
| 20.00 | 0.787 | C0200 | -211 | +0.22 |
| 21.20 | 0.835 | C0212 | -212 | +0.62 |
| 22.40 | 0.882 | C0224 | -212 | -0.58 |
| 23.60 | 0.929 | C0236 | -213 | -0.21 |
| 25.00 | 0.984 | C0250 | -214 | -0.01 |
| 25.80 | 1.016 | C0258 | -215 | +0.77 |
| 26.50 | 1.043 | C0265 | -215 | +0.07 |
| 28.00 | 1.102 | C0280 | -216 | +0.17 |
| 30.00 | 1.181 | C0300 | -217 | -0.26 |
| 31.50 | 1.240 | C0315 | -218 | -0.16 |
| 32.50 | 1.280 | C0325 | -219 | +0.42 |
| 33.50 | 1.319 | C0335 | -219 | -0.58 |
| 34.50 | 1.358 | C0345 | -220 | +0.02 |
| 35.50 | 1.398 | C0355 | -221 | +0.59 |
| 36.50 | 1.437 | C0365 | -221 | -0.41 |
| 37.50 | 1.476 | C0375 | -222 | +0.19 |
| 38.70 | 1.524 | C0387 | -222 | -1.01 |
| 40.00 | 1.575 | C0400 | -223 | +0.87 |
| 41.20 | 1.622 | C0412 | -223 | -0.33 |
| 42.50 | 1.673 | C0425 | -224 | +1.54 |
| 43.70 | 1.720 | C0437 | -224 | +0.34 |
| 45.00 | 1.772 | C0450 | -224 | -0.96 |
| 46.20 | 1.819 | C0462 | -225 | +1.02 |
| 47.50 | 1.870 | C0475 | -225 | -0.28 |
| 48.70 | 1.917 | C0487 | -225 | -1.48 |
| 50.00 | 1.969 | C0500 | -226 | +0.39 |
| 51.50 | 2.028 | C0515 | -226 | -1.11 |
| 53.00 | 2.087 | C0530 | -227 | +0.57 |
| 54.50 | 2.146 | C0545 | -227 | -0.93 |
| 56.00 | 2.205 | C0560 | -228 | +0.74 |
| 58.00 | 2.283 | C0580 | -228 | -1.26 |
| 60.00 | 2.362 | C0600 | -229 | -0.08 |
| 61.50 | 2.421 | C0615 | -229 | -1.58 |
| 63.00 | 2.480 | C0630 | -230 | +0.09 |
| 65.00 | 2.559 | C0650 | -231 | +1.27 |
| 67.00 | 2.638 | C0670 | -231 | -0.73 |
| 69.00 | 2.717 | C0690 | -232 | +0.44 |
| 71.00 | 2.795 | C0710 | -232 | -1.56 |
| 73.00 | 2.874 | C0730 | -233 | -0.38 |
| 75.00 | 2.953 | C0750 | -234 | +0.79 |
| 77.50 | 3.051 | C0775 | -235 | +1.47 |
| 80.00 | 3.150 | C0800 | -235 | -1.03 |
| 82.50 | 3.248 | C0825 | -236 | -0.36 |
| 85.00 | 3.346 | C0850 | -237 | +0.32 |
| 87.50 | 3.445 | C0875 | -238 | +0.99 |
| 90.00 | 3.543 | C0900 | -238 | -1.51 |
| 92.50 | 3.642 | C0925 | -239 | -0.83 |
| 95.00 | 3.740 | C0950 | -240 | -0.16 |
| 97.50 | 3.839 | C0975 | -241 | +0.52 |
| 100.00 | 3.937 | C1000 | -242 | +1.19 |
| 103.00 | 4.055 | C1030 | -243 | +1.37 |
| 106.00 | 4.173 | C1060 | -244 | +1.54 |
| 109.00 | 4.291 | C1090 | -244 | -1.46 |
| 112.00 | 4.409 | C1120 | -245 | -1.28 |
| 115.00 | 4.528 | C1150 | -246 | -1.11 |
| 118.00 | 4.646 | C1180 | -247 | -0.93 |
| 122.00 | 4.803 | C1220 | -249 | +1.42 |
| 125.00 | 4.921 | C1250 | -249 | -1.58 |
| 128.00 | 5.039 | C1280 | -250 | -1.41 |
| 132.00 | 5.197 | C1320 | -252 | +0.94 |
| 136.00 | 5.354 | C1360 | -253 | +0.12 |
| 140.00 | 5.512 | C1400 | -254 | -0.71 |
| 145.00 | 5.709 | C1450 | -256 | +0.64 |
| 150.00 | 5.906 | C1500 | -257 | -1.18 |
| 155.00 | 6.102 | C1550 | -258 | -3.01 |
| 160.00 | 6.299 | C1600 | -259 | -1.66 |
| 165.00 | 6.496 | C1650 | -260 | -0.31 |
| 170.00 | 6.693 | C1700 | -261 | +1.04 |
| 175.00 | 6.890 | C1750 | -262 | +2.39 |
| 180.00 | 7.087 | C1800 | -262 | -2.61 |
| 185.00 | 7.283 | C1850 | -263 | -1.26 |
| 190.00 | 7.480 | C1900 | -264 | +0.09 |
| 195.00 | 7.677 | C1950 | -265 | +1.44 |
| 200.00 | 7.874 | C2000 | -266 | +2.79 |
| 212.00 | 8.346 | C2120 | -267 | -2.86 |
| 218.00 | 8.583 | C2180 | -268 | -2.51 |
| 224.00 | 8.819 | C2240 | -269 | -2.16 |
| 230.00 | 9.055 | C2300 | -270 | -1.81 |
| 236.00 | 9.291 | C2360 | -271 | -1.46 |
| 250.00 | 9.843 | C2500 | -273 | -2.76 |
| 258.00 | 10.157 | C2580 | -274 | -4.41 |
| 265.00 | 10.433 | C2650 | -275 | +1.29 |
| 280.00 | 11.024 | C2800 | -276 | -1.01 |
| 290.00 | 11.417 | C2900 | -277 | +1.69 |
| 300.00 | 11.811 | C3000 | -278 | +4.39 |
| 307.00 | 12.087 | C3070 | -278 | -2.61 |
| 315.00 | 12.402 | C3150 | -278 | -10.61 |
| 335.00 | 13.189 | C3350 | -279 | -5.21 |
| 355.00 | 13.976 | C3550 | -280 | +0.19 |
Group D sizes, 5.30 mm (0.209 in) cross-section
| ID mm | ID in | ISO code | Nearest AS568 size, not an equivalent; the print governs | ID difference mm |
|---|---|---|---|---|
| 37.50 | 1.476 | D0375 | -325 | -0.03 |
| 38.70 | 1.524 | D0387 | -325 | -1.23 |
| 40.00 | 1.575 | D0400 | -326 | +0.64 |
| 41.20 | 1.622 | D0412 | -326 | -0.56 |
| 42.50 | 1.673 | D0425 | -327 | +1.32 |
| 43.70 | 1.720 | D0437 | -327 | +0.12 |
| 45.00 | 1.772 | D0450 | -327 | -1.18 |
| 46.20 | 1.819 | D0462 | -328 | +0.79 |
| 47.50 | 1.870 | D0475 | -328 | -0.51 |
| 48.70 | 1.917 | D0487 | -329 | +1.47 |
| 50.00 | 1.969 | D0500 | -329 | +0.17 |
| 51.50 | 2.028 | D0515 | -329 | -1.33 |
| 53.00 | 2.087 | D0530 | -330 | +0.34 |
| 54.50 | 2.146 | D0545 | -330 | -1.16 |
| 56.00 | 2.205 | D0560 | -331 | +0.52 |
| 58.00 | 2.283 | D0580 | -331 | -1.48 |
| 60.00 | 2.362 | D0600 | -332 | -0.31 |
| 61.50 | 2.421 | D0615 | -333 | +1.37 |
| 63.00 | 2.480 | D0630 | -333 | -0.13 |
| 65.00 | 2.559 | D0650 | -334 | +1.04 |
| 67.00 | 2.638 | D0670 | -334 | -0.96 |
| 69.00 | 2.717 | D0690 | -335 | +0.22 |
| 71.00 | 2.795 | D0710 | -336 | +1.39 |
| 73.00 | 2.874 | D0730 | -336 | -0.61 |
| 75.00 | 2.953 | D0750 | -337 | +0.57 |
| 77.50 | 3.051 | D0775 | -338 | +1.24 |
| 80.00 | 3.150 | D0800 | -338 | -1.26 |
| 82.50 | 3.248 | D0825 | -339 | -0.58 |
| 85.00 | 3.346 | D0850 | -340 | +0.09 |
| 87.50 | 3.445 | D0875 | -341 | +0.77 |
| 90.00 | 3.543 | D0900 | -342 | +1.44 |
| 92.50 | 3.642 | D0925 | -342 | -1.06 |
| 95.00 | 3.740 | D0950 | -343 | -0.38 |
| 97.50 | 3.839 | D0975 | -344 | +0.29 |
| 100.00 | 3.937 | D1000 | -345 | +0.97 |
| 103.00 | 4.055 | D1030 | -346 | +1.14 |
| 106.00 | 4.173 | D1060 | -347 | +1.32 |
| 109.00 | 4.291 | D1090 | -348 | +1.49 |
| 112.00 | 4.409 | D1120 | -348 | -1.51 |
| 115.00 | 4.528 | D1150 | -349 | -1.33 |
| 118.00 | 4.646 | D1180 | -350 | -1.16 |
| 122.00 | 4.803 | D1220 | -352 | +1.19 |
| 125.00 | 4.921 | D1250 | -353 | +1.37 |
| 128.00 | 5.039 | D1280 | -354 | +1.54 |
| 132.00 | 5.197 | D1320 | -355 | +0.72 |
| 136.00 | 5.354 | D1360 | -356 | -0.11 |
| 140.00 | 5.512 | D1400 | -357 | -0.93 |
| 145.00 | 5.709 | D1450 | -359 | +0.42 |
| 150.00 | 5.906 | D1500 | -360 | -1.41 |
| 155.00 | 6.102 | D1550 | -362 | +3.12 |
| 160.00 | 6.299 | D1600 | -362 | -1.88 |
| 165.00 | 6.496 | D1650 | -363 | -0.53 |
| 170.00 | 6.693 | D1700 | -364 | +0.82 |
| 175.00 | 6.890 | D1750 | -365 | +2.17 |
| 180.00 | 7.087 | D1800 | -365 | -2.83 |
| 185.00 | 7.283 | D1850 | -366 | -1.48 |
| 190.00 | 7.480 | D1900 | -367 | -0.13 |
| 195.00 | 7.677 | D1950 | -368 | +1.22 |
| 200.00 | 7.874 | D2000 | -369 | +2.57 |
Group E sizes, 7.00 mm (0.276 in) cross-section
| ID mm | ID in | ISO code | Nearest AS568 size, not an equivalent; the print governs | ID difference mm |
|---|---|---|---|---|
| 109.00 | 4.291 | E1090 | -425 | +4.67 |
| 112.00 | 4.409 | E1120 | -425 | +1.67 |
| 115.00 | 4.528 | E1150 | -425 | -1.33 |
| 118.00 | 4.646 | E1180 | -426 | -1.16 |
| 122.00 | 4.803 | E1220 | -428 | +1.19 |
| 125.00 | 4.921 | E1250 | -429 | +1.37 |
| 128.00 | 5.039 | E1280 | -430 | +1.54 |
| 132.00 | 5.197 | E1320 | -431 | +0.72 |
| 136.00 | 5.354 | E1360 | -432 | -0.11 |
| 140.00 | 5.512 | E1400 | -433 | -0.93 |
| 145.00 | 5.709 | E1450 | -435 | +0.42 |
| 150.00 | 5.906 | E1500 | -436 | -1.41 |
| 155.00 | 6.102 | E1550 | -438 | +3.12 |
| 160.00 | 6.299 | E1600 | -438 | -1.88 |
| 165.00 | 6.496 | E1650 | -439 | -0.53 |
| 170.00 | 6.693 | E1700 | -440 | +0.82 |
| 175.00 | 6.890 | E1750 | -441 | +2.17 |
| 180.00 | 7.087 | E1800 | -441 | -2.83 |
| 185.00 | 7.283 | E1850 | -442 | -1.48 |
| 190.00 | 7.480 | E1900 | -443 | -0.13 |
| 195.00 | 7.677 | E1950 | -444 | +1.22 |
| 200.00 | 7.874 | E2000 | -445 | +2.57 |
| 206.00 | 8.110 | E2060 | -445 | -3.43 |
| 212.00 | 8.346 | E2120 | -446 | +3.27 |
| 218.00 | 8.583 | E2180 | -446 | -2.73 |
| 224.00 | 8.819 | E2240 | -447 | +3.97 |
| 230.00 | 9.055 | E2300 | -447 | -2.03 |
| 236.00 | 9.291 | E2360 | -448 | +4.67 |
| 243.00 | 9.567 | E2430 | -448 | -2.33 |
| 250.00 | 9.843 | E2500 | -449 | +3.37 |
| 258.00 | 10.157 | E2580 | -449 | -4.63 |
| 265.00 | 10.433 | E2650 | -450 | +1.07 |
| 272.00 | 10.709 | E2720 | -450 | -5.93 |
| 280.00 | 11.024 | E2800 | -451 | -1.23 |
| 290.00 | 11.417 | E2900 | -452 | +1.47 |
| 300.00 | 11.811 | E3000 | -453 | +4.17 |
| 307.00 | 12.087 | E3070 | -453 | -2.83 |
| 315.00 | 12.402 | E3150 | -454 | +1.87 |
| 325.00 | 12.795 | E3250 | -455 | +4.57 |
| 335.00 | 13.189 | E3350 | -455 | -5.43 |
| 345.00 | 13.583 | E3450 | -456 | -2.73 |
| 355.00 | 13.976 | E3550 | -457 | -0.03 |
| 365.00 | 14.370 | E3650 | -458 | +2.67 |
| 375.00 | 14.764 | E3750 | -459 | +5.37 |
| 387.00 | 15.236 | E3870 | -460 | +6.07 |
| 400.00 | 15.748 | E4000 | -461 | +5.26 |
Frequently asked
How do I read an ISO 3601-1 size code such as C0250?
The letter is the cross-section group and the four digits give the inside diameter to the nearest tenth of a millimeter. C0250 is group C, 3.55 mm cross-section, with a 25.0 mm inside diameter. The same ring is often written 25.0 x 3.55 on a drawing. Some diameters are not a round tenth: A0032 is 3.15 mm, so read the inside diameter from the list, not from the code.
Is an AS568 size in millimeters an ISO 3601-1 metric size?
No. AS568 sizes converted to millimeters keep their inch cords (1.78, 2.62, 3.53, 5.33 and 6.99 mm) and their inch diameters. The ISO 3601-1 metric sizes on this page use the 1.80, 2.65, 3.55, 5.30 and 7.00 mm cords and metric inside diameters. Read the cross-section on your print first; it tells you which list the ring comes from.
What is the nearest AS568 size to C0250?
AS568-214, 24.99 x 3.53 mm, is the nearest AS568 size, not an equivalent; the print governs. Its inside diameter differs from C0250's by -0.01 mm and its cord by -0.02 mm. Whether a ring from the other list fits your gland is a decision for your engineering and your print, not a reading from this page.
What if my metric size is not in this list?
Many metric rings, such as 20 x 2 mm, are not in the ISO 3601-1 metric list. Send the inside diameter, the cross-section and the compound from your print and we quote it as drawn. A Conquest representative replies within one business day.
Orders are handled under Conquest Seal's AS9100D quality management system, whose certificate scope includes distribution.
Need a metric O-ring quoted?
Send the ISO 3601-1 code, or the inside diameter and cross-section from your print, with the compound and the quantity. A Conquest representative replies within one business day.
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