O rings are commonly used components which are used in wide range of industrial equipment. These are available in various sizes and shapes as per the requirements and are manufactured as per the globally recognized industrial standards. The most common and popular standard for describing O ring size is AS568 which is used in United States and is published by S.A.E. (Society of Automotive Engineers). It specifies O ring sizes as “Inch sizes”.

O ring sizes can be described by various O ring standard size charts used across the globe. Each size chart shows O ring sizes as per there country norms and industrial specifications.

O ring sizes as per some of the common size charts are shown below:

• AS568

Series
C/S Inches
C/S Frac.
C/S mm
ID Range
Zero
.070
1/16
1.78
.029 – 5.239″
100
.103
3/32
2.62
.049 – 9.737″
200
.139
1/8
3.53
.171 – 17.955″
300
.210
3/16
5.33
.412 – 25.940″
400
.275
1/4
6.99
1.350 – 25.940″
900
varies
varies
1.42 – 3.0
.185 – 2.337″

• BS 1806

Global Part #
Reference
C/S (MM)
I.D. (MM)
C/S (Inch)
I.D. (Inch)
1.02X000.74
-001
1.020
0.740
0.040
0.029
1.02X001.78
-606
1.020
1.780
0.040
0.070
1.02X002.54
-607
1.020
2.540
0.040
0.100
1.27X001.07
-002
1.270
1.070
0.050
0.042
1.52X001.42
-003
1.520
1.420
0.060
0.056

• ISO 3601

Global Part #
Reference
C/S (MM)
I.D. (MM)
C/S (Inch)
I.D. (Inch)
1.80X001.8
A0018
1.8
1.8
0.071
0.071
1.80X002
A0020
1.8
2
0.071
0.079
1.80X002.24
A0022
1.8
2.24
0.071
0.088
1.80X002.5
A0025
1.8
2.5
0.071
0.098
1.80X002.8
A0028
1.8
2.8
0.071
0.11

• BS 4518

Global Part #
Reference
C/S (MM)
I.D. (MM)
C/S (Inch)
I.D. (Inch)
1.60X003.1
0031-16
1.600
3.100
0.063
0.122
1.60X004.1
0041-16
1.600
4.100
0.063
0.161
1.60X005.1
0051-16
1.600
5.100
0.063
0.201
1.60X006.1
0061-16
1.600
6.100
0.063
0.240
1.60X007.1
0071-16
1.600
7.100
0.063
0.280

• SMS 1586

Global Part #
Reference
C/S (MM)
I.D. (MM)
C/S (Inch)
I.D. (Inch)
1.60X003.1
S 3.1 x 1.6
1.600
3.100
0.063
0.122
1.60X004.1
S 4.1 x 1.6
1.600
4.100
0.063
0.161
1.60X005.1
S 5.1 x 1.6
1.600
5.100
0.063
0.201
1.60X006.1
S 6.1 x 1.6
1.600
6.100
0.063
0.240
1.60X007.1
S 7.1 x 1.6
1.600
7.100
0.063
0.280

• DIN 3771

Global Part #
Reference
C/S (MM)
I.D. (MM)
C/S (Inch)
I.D. (Inch)
1.80X001.8
1.8 X 1.8
1.800
1.800
0.071
0.071
1.80X002
2 X 1.8
1.800
2.000
0.071
0.079
1.80X002.24
2.24 X 1.8
1.800
2.240
0.071
0.088
1.80X002.5
2.5 X 1.8
1.800
2.500
0.071
0.098
1.80X002.8
2.8 X 1.8
1.800
2.800
0.071
0.110

• NFT 47-501

Global Part #
Reference
C/S (MM)
I.D. (MM)
C/S (Inch)
I.D. (Inch)
1.80X001.8
01/29/2019
1.800
1.800
0.071
0.071
1.80X002
01/29/2019
1.800
2.000
0.071
0.079
1.80X002.24
01/29/2019
1.800
2.240
0.071
0.088
1.80X002.5
01/29/2019
1.800
2.500
0.071
0.098
1.80X002.8
01/29/2019
1.800
2.800
0.071
0.110

• JIS B 2401 - It has 4 series viz, P series, G series, S series and V series

JIS P series -

Global Part #
Reference
C/S (MM)
I.D. (MM)
1.90X002.8
P3
1.900
2.800
1.90X003.8
P4
1.900
3.800
1.90X004.8
P5
1.900
4.800
1.90X005.8
P6
1.900
5.800
1.90X006.8
P7
1.900
6.800

JIS G series -

Global Part #
Reference
C/S (MM)
I.D. (MM)
3.10X024.4
G25
3.100
24.400
3.10X029.4
G30
3.100
29.400
3.10X034.4
G35
3.100
34.400
3.10X039.4
G40
3.100
39.400
3.10X044.4
G45
3.100
44.400

JIS S series -

Global Part #
Reference
C/S (MM)
I.D. (MM)
1.50X002.5
S-3
1.500
2.500
1.50X003.5
S-4
1.500
3.500
1.50X004.5
S-5
1.500
4.500
1.50X005.5
S-6
1.500
5.500
1.50X006.5
S-7
1.500
6.500

JIS V series -

Global Part #
Reference
C/S (MM)
I.D. (MM)
10.00X1044
V-1055
10.000
1,044.000
10.00X475
V-480
10.000
475.000
10.00X524.5
V-530
10.000
524.500
10.00X579
V-585
10.000
579.000
10.00X633.5
V-640
10.000
633.500

• ISO 6149

Global Part #
Reference
C/S (MM)
I.D. (MM)
C/S (Inch)
I.D. (Inch)
1.60X006.1
M8 X 1
1.600
6.100
0.063
0.240
1.60X008.1
M10 X 1
1.600
8.100
0.063
0.319
2.20X009.3
M12 X 1.5
2.200
9.300
0.087
0.366
2.20X011.3
M14 X 1.5
2.200
11.300
0.087
0.445
2.20X013.3
M16 X 1.5
2.200
13.300
0.087
0.524
2.20X015.3
M18 X 1.5
2.200
15.300
0.087
0.602
2.20X017.3
M20 X 1.5
2.200
17.300
0.087
0.681
2.20X019.3
M22 X 1.5
2.200
19.300
0.087
0.760
2.90X023.6
M27 X 2
2.900
23.600
0.114
0.929
2.90X029.6
M33 X 2
2.900
29.600
0.114
1.165
2.90X038.6
M42 X 2
2.900
38.600
0.114
1.520
2.90X044.6
M48 X 2
2.900
44.600
0.114
1.756
2.90X056.6
M60 X 2
2.900
56.600
0.114
2.228

• Generic Metric O ring sizing

Global Part #ReferenceC/S (MM)I.D. (MM)0.97X002.540.97x2.540.9702.5401.00X0011x11.0001.0001.00X001.51x1.51.0001.5001.00X001.781x1.781.0001.7801.00X0021x21.0002.000