DIN 3771 Metric O-Ring Size Chart

DIN 3771 is the German metric O-ring standard, where a size is called out as inside diameter x cross-section in millimeters, with optional quality-level and hardness codes. Engineers use this chart to translate a DIN 3771 callout into an exact ID, cross-section and grade; ARC molds every size to spec in your required compound and hardness.

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Using the DIN 3771 chart to spec your O-ring

DIN 3771 is the German metric O-ring size standard engineers reach for when a drawing calls out a seal as inside diameter x cross-section in millimeters rather than a dash number. Read across the chart to translate a DIN 3771 callout into the exact ID and cross-section (CS) you need, then confirm the quality level and hardness code that go with it — the quality grade governs allowable surface and molding defects, and the hardness code sets the durometer (Shore A) for your groove and duty. Buyers searching DIN 3771 metric O-ring sizes use this table to lock the ID x CS, grade and hardness before release, so the seal fits its groove and passes incoming inspection the first time.

Once you have the size, grade and hardness, ARC molds it to your spec. Twenty years of US custom rubber manufacturing, ISO 9001:2015 and IATF 16949:2016 certification, and a full range of compounds — NBR, HNBR, FKM/Viton, EPDM, silicone and more — mean you choose the material and durometer for your temperature, pressure and chemical duty while we hold the DIN 3771 dimensions and quality level you specify. Send the ID x cross-section, quality level and hardness, or a drawing, and our engineers confirm compound, tolerances and a fast quote.

DIN 3771 Metric O-Rings

The DIN 3771 o-ring standard is issued by The German Institute for Standards (Duetsches Institut für Normung). This standard identifies O-Ring sizes by the ID x C/S, and may be followed by a letter indicating the quality level (N – normal quality; S – special quality), and a code indicating the rubber polymer and IRHD hardness.

For a complete listing of all metric o-ring sizes, visit our Metric O-Ring Cross Reference Table.

DIN 3771 Size Chart

Global Part#	Reference	C/S (MM)	I.D. (MM)	C/S (Inch)	I.D. (Inch)
1.80X001.8	1.8 X 1.8	1.8	1.8	0.071	0.071
1.80X002	2 X 1.8	1.8	2	0.071	0.079
1.80X002.24	2.24 X 1.8	1.8	2.24	0.071	0.088
1.80X002.5	2.5 X 1.8	1.8	2.5	0.071	0.098
1.80X002.8	2.8 X 1.8	1.8	2.8	0.071	0.11
1.80X003.15	3.15 X 1.8	1.8	3.15	0.071	0.124
1.80X003.55	3.55 X 1.8	1.8	3.55	0.071	0.14
1.80X003.75	3.75 X 1.8	1.8	3.75	0.071	0.148
1.80X004	4 X 1.8	1.8	4	0.071	0.157
1.80X004.5	4.5 X 1.8	1.8	4.5	0.071	0.177
1.80X004.87	4.87 X 1.8	1.8	4.87	0.071	0.192
1.80X005	5 X 1.8	1.8	5	0.071	0.197
1.80X005.15	5.15 X 1.8	1.8	5.15	0.071	0.203
1.80X005.3	5.3 X 1.8	1.8	5.3	0.071	0.209
1.80X005.6	5.6 X 1.8	1.8	5.6	0.071	0.22
1.80X006	6 X 1.8	1.8	6	0.071	0.236
1.80X006.3	6.3 X 1.8	1.8	6.3	0.071	0.248
1.80X006.7	6.7 X 1.8	1.8	6.7	0.071	0.264
1.80X006.9	6.9 X 1.8	1.8	6.9	0.071	0.272
1.80X007.1	7.1 X 1.8	1.8	7.1	0.071	0.28
1.80X007.5	7.5 X 1.8	1.8	7.5	0.071	0.295
1.80X008	8 X 1.8	1.8	8	0.071	0.315
1.80X008.5	8.5 X 1.8	1.8	8.5	0.071	0.335
1.80X008.75	8.75 X 1.8	1.8	8.75	0.071	0.344
1.80X009	9 X 1.8	1.8	9	0.071	0.354
1.80X009.5	9.5 X 1.8	1.8	9.5	0.071	0.374
1.80X010	10 X 1.8	1.8	10	0.071	0.394
1.80X010.6	10.6 X 1.8	1.8	10.6	0.071	0.417
1.80X011.2	11.2 X 1.8	1.8	11.2	0.071	0.441
1.80X011.8	11.8 X 1.8	1.8	11.8	0.071	0.465
1.80X012.5	12.5 X 1.8	1.8	12.5	0.071	0.492
1.80X013.2	13.2 X 1.8	1.8	13.2	0.071	0.52
1.80X014	14 X 1.8	1.8	14	0.071	0.551
1.80X015	15 X 1.8	1.8	15	0.071	0.591
1.80X016	16 X 1.8	1.8	16	0.071	0.63
1.80X017	17 X 1.8	1.8	17	0.071	0.669
2.65X014	14 X 2.65	2.65	14	0.104	0.551
2.65X015	15 X 2.65	2.65	15	0.104	0.591
2.65X016	16 X 2.65	2.65	16	0.104	0.63
2.65X017	17 X 2.65	2.65	17	0.104	0.669
2.65X018	18 X 2.65	2.65	18	0.104	0.709
2.65X019	19 X 2.65	2.65	19	0.104	0.748
2.65X020	20 X 2.65	2.65	20	0.104	0.787
2.65X021.2	21.2 X 2.65	2.65	21.2	0.104	0.835
2.65X022.4	22.4 X 2.65	2.65	22.4	0.104	0.882
2.65X023.6	23.6 X 2.65	2.65	23.6	0.104	0.929
2.65X025	25 X 2.65	2.65	25	0.104	0.984
2.65X025.8	25.8 X 2.65	2.65	25.8	0.104	1.016
2.65X026.5	26.5 X 2.65	2.65	26.5	0.104	1.043
2.65X028	28 X 2.65	2.65	28	0.104	1.102
2.65X030	30 X 2.65	2.65	30	0.104	1.181
2.65X031.5	31.5 X 2.65	2.65	31.5	0.104	1.24
2.65X032.5	32.5 X 2.65	2.65	32.5	0.104	1.28
2.65X033.5	33.5 X 2.65	2.65	33.5	0.104	1.319
2.65X034.5	34.5 X 2.65	2.65	34.5	0.104	1.358
2.65X035.5	35.5 X 2.65	2.65	35.5	0.104	1.398
2.65X036.5	36.5 X 2.65	2.65	36.5	0.104	1.437
2.65X037.5	37.5 X 2.65	2.65	37.5	0.104	1.476
2.65X038.7	38.7 X 2.65	2.65	38.7	0.104	1.524
3.55X018	18 X 3.55	3.55	18	0.14	0.709
3.55X019	19 X 3.55	3.55	19	0.14	0.748
3.55X020	20 X 3.55	3.55	20	0.14	0.787
3.55X021.2	21.2 X 3.55	3.55	21.2	0.14	0.835
3.55X022.4	22.4 X 3.55	3.55	22.4	0.14	0.882
3.55X023.6	23.6 X 3.55	3.55	23.6	0.14	0.929
3.55X025	25 X 3.55	3.55	25	0.14	0.984
3.55X025.8	25.8 X 3.55	3.55	25.8	0.14	1.016
3.55X026.5	26.5 X 3.55	3.55	26.5	0.14	1.043
3.55X028	28 X 3.55	3.55	28	0.14	1.102
3.55X030	30 X 3.55	3.55	30	0.14	1.181
3.55X031.5	31.5 X 3.55	3.55	31.5	0.14	1.24
3.55X032.5	32.5 X 3.55	3.55	32.5	0.14	1.28
3.55X033.5	33.5 X 3.55	3.55	33.5	0.14	1.319
3.55X034.5	34.5 X 3.55	3.55	34.5	0.14	1.358
3.55X035.5	35.5 X 3.55	3.55	35.5	0.14	1.398
3.55X036.5	36.5 X 3.55	3.55	36.5	0.14	1.437
3.55X037.5	37.5 X 3.55	3.55	37.5	0.14	1.476
3.55X038.7	38.7 X 3.55	3.55	38.7	0.14	1.524
3.55X040	40 X 3.55	3.55	40	0.14	1.575
3.55X041.2	41.2 X 3.55	3.55	41.2	0.14	1.622
3.55X042.5	42.5 X 3.55	3.55	42.5	0.14	1.673
3.55X043.7	43.7 X 3.55	3.55	43.7	0.14	1.72
3.55X045	45 X 3.55	3.55	45	0.14	1.772
3.55X046.2	46.2 X 3.55	3.55	46.2	0.14	1.819
3.55X047.5	47.5 X 3.55	3.55	47.5	0.14	1.87
3.55X048.7	48.7 X 3.55	3.55	48.7	0.14	1.917
3.55X050	50 X 3.55	3.55	50	0.14	1.969
3.55X051.5	51.5 X 3.55	3.55	51.5	0.14	2.028
3.55X053	53 X 3.55	3.55	53	0.14	2.087
3.55X054.5	54.5 X 3.55	3.55	54.5	0.14	2.146
3.55X056	56 X 3.55	3.55	56	0.14	2.205
3.55X058	58 X 3.55	3.55	58	0.14	2.283
3.55X060	60 X 3.55	3.55	60	0.14	2.362
3.55X061.5	61.5 X 3.55	3.55	61.5	0.14	2.421
3.55X063	63 X 3.55	3.55	63	0.14	2.48
3.55X065	65 X 3.55	3.55	65	0.14	2.559
3.55X067	67 X 3.55	3.55	67	0.14	2.638
3.55X069	69 X 3.55	3.55	69	0.14	2.717
3.55X071	71 X 3.55	3.55	71	0.14	2.795
3.55X073	73 X 3.55	3.55	73	0.14	2.874
3.55X075	75 X 3.55	3.55	75	0.14	2.953
3.55X077.5	77.5 X 3.55	3.55	77.5	0.14	3.051
3.55X080	80 X 3.55	3.55	80	0.14	3.15
3.55X082.5	82.5 X 3.55	3.55	82.5	0.14	3.248
3.55X085	85 X 3.55	3.55	85	0.14	3.346
3.55X087.5	87.5 X 3.55	3.55	87.5	0.14	3.445
3.55X090	90 X 3.55	3.55	90	0.14	3.543
3.55X092.5	92.5 X 3.55	3.55	92.5	0.14	3.642
3.55X095	95 X 3.55	3.55	95	0.14	3.74
3.55X097.5	97.5 X 3.55	3.55	97.5	0.14	3.839
3.55X100	100 X 3.55	3.55	100	0.14	3.937
3.55X103	103 X 3.55	3.55	103	0.14	4.055
3.55X106	106 X 3.55	3.55	106	0.14	4.173
3.55X109	109 X 3.55	3.55	109	0.14	4.291
3.55X112	112 X 3.55	3.55	112	0.14	4.409
3.55X115	115 X 3.55	3.55	115	0.14	4.528
3.55X118	118 X 3.55	3.55	118	0.14	4.646
3.55X122	122 X 3.55	3.55	122	0.14	4.803
3.55X125	125 X 3.55	3.55	125	0.14	4.921
3.55X128	128 X 3.55	3.55	128	0.14	5.039
3.55X132	132 X 3.55	3.55	132	0.14	5.197
3.55X136	136 X 3.55	3.55	136	0.14	5.354
3.55X140	140 X 3.55	3.55	140	0.14	5.512
3.55X145	145 X 3.55	3.55	145	0.14	5.709
3.55X150	150 X 3.55	3.55	150	0.14	5.906
3.55X155	155 X 3.55	3.55	155	0.14	6.102
3.55X160	160 X 3.55	3.55	160	0.14	6.299
3.55X165	165 X 3.55	3.55	165	0.14	6.496
3.55X170	170 X 3.55	3.55	170	0.14	6.693
3.55X175	175 X 3.55	3.55	175	0.14	6.89
3.55X180	180 X 3.55	3.55	180	0.14	7.087
3.55X185	185 X 3.55	3.55	185	0.14	7.283
3.55X190	190 X 3.55	3.55	190	0.14	7.48
3.55X195	195 X 3.55	3.55	195	0.14	7.677
3.55X200	200 X 3.55	3.55	200	0.14	7.874
5.30X040	40 X 5.3	5.3	40	0.209	1.575
5.30X041.2	41.2 X 5.3	5.3	41.2	0.209	1.622
5.30X042.5	42.5 X 5.3	5.3	42.5	0.209	1.673
5.30X043.7	43.7 X 5.3	5.3	43.7	0.209	1.72
5.30X045	45 X 5.3	5.3	45	0.209	1.772
5.30X046.2	46.2 X 5.3	5.3	46.2	0.209	1.819
5.30X047.5	47.5 X 5.3	5.3	47.5	0.209	1.87
5.30X048.7	48.7 X 5.3	5.3	48.7	0.209	1.917
5.30X050	50 X 5.3	5.3	50	0.209	1.969
5.30X051.5	51.5 X 5.3	5.3	51.5	0.209	2.028
5.30X053	53 X 5.3	5.3	53	0.209	2.087
5.30X054.5	54.5 X 5.3	5.3	54.5	0.209	2.146
5.30X056	56 X 5.3	5.3	56	0.209	2.205
5.30X058	58 X 5.3	5.3	58	0.209	2.283
5.30X060	60 X 5.3	5.3	60	0.209	2.362
5.30X061.5	61.5 X 5.3	5.3	61.5	0.209	2.421
5.30X063	63 X 5.3	5.3	63	0.209	2.48
5.30X065	65 X 5.3	5.3	65	0.209	2.559
5.30X067	67 X 5.3	5.3	67	0.209	2.638
5.30X069	69 X 5.3	5.3	69	0.209	2.717
5.30X071	71 X 5.3	5.3	71	0.209	2.795
5.30X073	73 X 5.3	5.3	73	0.209	2.874
5.30X075	75 X 5.3	5.3	75	0.209	2.953
5.30X077.5	77.5 X 5.3	5.3	77.5	0.209	3.051
5.30X080	80 X 5.3	5.3	80	0.209	3.15
5.30X082.5	82.5 X 5.3	5.3	82.5	0.209	3.248
5.30X085	85 X 5.3	5.3	85	0.209	3.346
5.30X087.5	87.5 X 5.3	5.3	87.5	0.209	3.445
5.30X090	90 X 5.3	5.3	90	0.209	3.543
5.30X092.5	92.5 X 5.3	5.3	92.5	0.209	3.642
5.30X095	95 X 5.3	5.3	95	0.209	3.74
5.30X097.5	97.5 X 5.3	5.3	97.5	0.209	3.839
5.30X100	100 X 5.3	5.3	100	0.209	3.937
5.30X103	103 X 5.3	5.3	103	0.209	4.055
5.30X106	106 X 5.3	5.3	106	0.209	4.173
5.30X109	109 X 5.3	5.3	109	0.209	4.291
5.30X112	112 X 5.3	5.3	112	0.209	4.409
5.30X115	115 X 5.3	5.3	115	0.209	4.528
5.30X118	118 X 5.3	5.3	118	0.209	4.646
5.30X122	122 X 5.3	5.3	122	0.209	4.803
5.30X125	125 X 5.3	5.3	125	0.209	4.921
5.30X128	128 X 5.3	5.3	128	0.209	5.039
5.30X132	132 X 5.3	5.3	132	0.209	5.197
5.30X136	136 X 5.3	5.3	136	0.209	5.354
5.30X140	140 X 5.3	5.3	140	0.209	5.512
5.30X145	145 X 5.3	5.3	145	0.209	5.709
5.30X150	150 X 5.3	5.3	150	0.209	5.906
5.30X155	155 X 5.3	5.3	155	0.209	6.102
5.30X160	160 X 5.3	5.3	160	0.209	6.299
5.30X165	165 X 5.3	5.3	165	0.209	6.496
5.30X170	170 X 5.3	5.3	170	0.209	6.693
5.30X175	175 X 5.3	5.3	175	0.209	6.89
5.30X180	180 X 5.3	5.3	180	0.209	7.087
5.30X185	185 X 5.3	5.3	185	0.209	7.283
5.30X190	190 X 5.3	5.3	190	0.209	7.48
5.30X195	195 X 5.3	5.3	195	0.209	7.677
5.30X200	200 X 5.3	5.3	200	0.209	7.874
5.30X206	206 X 5.3	5.3	206	0.209	8.11
5.30X212	212 X 5.3	5.3	212	0.209	8.346
5.30X218	218 X 5.3	5.3	218	0.209	8.583
5.30X224	224 X 5.3	5.3	224	0.209	8.819
5.30X230	230 X 5.3	5.3	230	0.209	9.055
5.30X236	236 X 5.3	5.3	236	0.209	9.291
5.30X243	243 X 5.3	5.3	243	0.209	9.567
5.30X250	250 X 5.3	5.3	250	0.209	9.843
5.30X258	258 X 5.3	5.3	258	0.209	10.157
5.30X265	265 X 5.3	5.3	265	0.209	10.433
5.30X272	272 X 5.3	5.3	272	0.209	10.709
5.30X280	280 X 5.3	5.3	280	0.209	11.024
5.30X290	290 X 5.3	5.3	290	0.209	11.417
5.30X300	300 X 5.3	5.3	300	0.209	11.811
5.30X307	307 X 5.3	5.3	307	0.209	12.087
5.30X315	315 X 5.3	5.3	315	0.209	12.402
5.30X325	325 X 5.3	5.3	325	0.209	12.795
5.30X335	335 X 5.3	5.3	335	0.209	13.189
5.30X345	345 X 5.3	5.3	345	0.209	13.583
5.30X355	355 X 5.3	5.3	355	0.209	13.976
5.30X365	365 X 5.3	5.3	365	0.209	14.37
5.30X375	375 X 5.3	5.3	375	0.209	14.764
5.30X387	387 X 5.3	5.3	387	0.209	15.236
5.30X400	400 X 5.3	5.3	400	0.209	15.748
7.00X206	206 X 7	7	206	0.276	8.11
7.00X212	212 X 7	7	212	0.276	8.346
7.00X218	218 X 7	7	218	0.276	8.583
7.00X224	224 X 7	7	224	0.276	8.819
7.00X230	230 X 7	7	230	0.276	9.055
7.00X236	236 X 7	7	236	0.276	9.291
7.00X243	243 X 7	7	243	0.276	9.567
7.00X250	250 X 7	7	250	0.276	9.843
7.00X258	258 X 7	7	258	0.276	10.157
7.00X265	265 X 7	7	265	0.276	10.433
7.00X272	272 X 7	7	272	0.276	10.709
7.00X280	280 X 7	7	280	0.276	11.024
7.00X290	290 X 7	7	290	0.276	11.417
7.00X300	300 X 7	7	300	0.276	11.811
7.00X307	307 X 7	7	307	0.276	12.087
7.00X315	315 X 7	7	315	0.276	12.402
7.00X325	325 X 7	7	325	0.276	12.795
7.00X335	335 X 7	7	335	0.276	13.189
7.00X345	345 X 7	7	345	0.276	13.583
7.00X355	355 X 7	7	355	0.276	13.976
7.00X365	365 X 7	7	365	0.276	14.37
7.00X375	375 X 7	7	375	0.276	14.764
7.00X387	387 X 7	7	387	0.276	15.236
7.00X400	400 X 7	7	400	0.276	15.748
7.00X412	412 X 7	7	412	0.276	16.22
7.00X425	425 X 7	7	425	0.276	16.732
7.00X437	437 X 7	7	437	0.276	17.205
7.00X450	450 X 7	7	450	0.276	17.717
7.00X462	462 X 7	7	462	0.276	18.189
7.00X475	475 X 7	7	475	0.276	18.701
7.00X487	487 X 7	7	487	0.276	19.173
7.00X500	500 X 7	7	500	0.276	19.685
7.00X515	515 X 7	7	515	0.276	20.276
7.00X530	530 X 7	7	530	0.276	20.866
7.00X545	545 X 7	7	545	0.276	21.457
7.00X560	560 X 7	7	560	0.276	22.047
7.00X580	580 X 7	7	580	0.276	22.835
7.00X600	600 X 7	7	600	0.276	23.622
7.00X615	615 X 7	7	615	0.276	24.213
7.00X630	630 X 7	7	630	0.276	24.803
7.00X650	650 X 7	7	650	0.276	25.591
7.00X670	670 X 7	7	670	0.276	26.378
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DIN 3771 Metric O-Ring Size Chart

Using the DIN 3771 chart to spec your O-ring

DIN 3771 Metric O-Rings

DIN 3771 Size Chart

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