Body Jewelry Conversion Chart: Gauge, Inch, and Millimeter
We noticed there were mostly inaccurate charts posted online with conflicting information,
so we created this to end all confusion between different measuring systems.
This chart works for converting fractional inches, decimal inches, gauges (ga),
and millimeters (mm). This chart assumes 25.4mm equals 1" exactly.
Body jewelry in the US is made using the Brown and Sharp Wire Gauge system.
Gauge is sometimes spelled gage, or misspelled guage, and is abbreviated as ga.
This system is based on two assumptions, that 36ga is .005" and that 0000ga is 0.4600" in diameter.
The diameter of each gauge is 0.890525 times the diameter of the previous size,
if counting backwards from 0000ga,
or 1.1229331 times the previous size, if counting forwards from 36ga.
We frequently get asked the question: what size comes after 00ga?
Gauge sizes are not normally used beyond 00ga for measuring body piercing jewelry,
thus, the next size jump up past 00ga is generally agreed to be 7/16".
Those stretching beyond that usually use fractional inches to describe the size of their body piercings.
Gauge or Fractional Inches
Decimal inches
Metric (mm)
Circumference aka (2 x π x Radius) aka (Diameter x π)
1/64"
0.0156"
0.397 mm
.049"
26ga
0.0159"
0.404 mm
.04995"
25ga
0.0179"
0.4547 mm
.0562"
24ga
0.0201"
0.511 mm
.0631"
23ga
0.0226"
0.574 mm
.0710"
22ga
0.0253"
0.643 mm
.0795"
21ga
0.02846"
0.723 mm
.0894"
2/64" (1/32")
0.0313"
0.794 mm
.098"
20ga
0.0320"
0.812 mm
.101"
19ga
0.0359"
0.912 mm
.113"
0.039"
1.0 mm
.123"= 3.14mm
18ga
0.040"
1.02 mm
.126"
17ga
0.045"
1.14 mm
.141"
3/64"
0.047"
1.19 mm
.148"
16ga
0.051"
1.3 mm
.160"
15ga
0.057"
1.45 mm
.179"
4/64" (1/16")
0.0625"
1.59 mm
.19635"= 4.99mm
14ga
0.064"
1.6 mm
.201"
13ga
0.072"
1.8 mm
.226"
5/64"
0.078"
1.98 mm
.245"
0.079"
2.0 mm
.248"= 6.28mm
12ga
0.081"
2.06 mm
.254"
11ga
0.091"
2.3 mm
.286"
6/64" (3/32")
0.094"
2.38 mm
.295"
10ga
0.102"
2.6 mm
.320"
7/64"
0.109"
2.78 mm
.342"
9ga
0.114"
2.9 mm
.358"
0.118"
3.0 mm
.371"= 9.42mm
8/64" (1/8")
0.125"
3.18 mm
.393"
8ga
0.12849"
3.26 mm
.404"
9/64"
0.141"
3.57 mm
.443"
7ga
0.144"
3.66 mm
.452"
10/64" (5/32")
0.156"
3.97 mm
.490"
0.157"
4.0 mm
.493"= 12.57mm
6ga
0.162"
4.1 mm
.509"
11/64"
0.172"
4.37 mm
.540"
5ga
0.182"
4.6 mm
.572"
12/64" (3/16")
0.1875"
4.76 mm
.59"
0.197"
5.0 mm
.619"= 15.70mm
13/64"
0.203"
5.16 mm
.638"
4ga
0.204"
5.2 mm
.641"
14/64" (7/32")
0.219"
5.56 mm
.688"
3ga
0.229"
5.8 mm
.719"
15/64"
0.234"
5.95 mm
.735"
0.236"
6.0 mm
.741"= 18.85mm
16/64" (1/4")
0.250"
6.35 mm
.785"
2ga
0.2576"
6.54 mm
.809"
17/64"
0.266"
6.747 mm
.836"
0.276"
7.0 mm
.867"= 21.99mm
18/64" (9/32")
0.281"
7.14 mm
.883"
1ga
0.289"
7.3 mm
.908"
19/64"
0.297"
7.54 mm
.933"
20/64" (5/16")
0.3125"
7.94 mm
.98"
0.315"
8.0 mm
.9896"= 25.13mm
0ga
0.3249"
8.2525 mm
1.021"
21/64"
0.328"
8.33 mm
1.030"
22/64" (11/32")
0.344"
8.73 mm
1.081"
0.354"
9.0 mm
1.112"= 28.27mm
23/64"
0.359"
9.13 mm
1.128"
00ga
0.3648"
9.266 mm
1.146"
24/64" (3/8")
0.375"
9.53 mm
1.178"
25/64"
0.391"
9.92 mm
1.228"
0.394"
10.0 mm
1.238"= 31.42mm
26/64" (13/32")
0.406"
10.32 mm
1.275"
000ga
0.4096"
10.4 mm
1.287"
27/64"
0.422"
10.72 mm
1.326"
0.433"
11.0 mm
1.360"= 34.56mm
28/64" (7/16")
0.4375"
11.11 mm
1.374"
29/64"
0.453"
11.51 mm
1.423"
0000ga
0.460"
11.68 mm
1.445"
30/64" (15/32")
0.469"
11.91 mm
1.473"
0.472"
12.0 mm
1.483"= 37.70mm
31/64"
0.484"
12.30 mm
1.521"
1/2" (32/64")
0.500"
12.70 mm
1.571"
0.512"
13.0 mm
40.84mm
00000ga
0.517"
13.12 mm
1.623"
0.551"
14.0 mm
43.98mm
9/16" (36/64")
0.5625"
14.28 mm
1.767"
000000ga
0.580"
14.73 mm
1.822"
0.591"
15.0 mm
47.12mm
5/8" (40/64")
0.625"
15.87 mm
1.963"
0.630"
16.0 mm
50.27mm
0.669"
17.0 mm
53.41mm
11/16" (44/64")
0.6875"
17.46 mm
2.160"
0.709"
18.0 mm
56.55mm
0.748"
19.0 mm
59.69mm
3/4" (48/64")
0.750"
19.05 mm
2.356"
0.787"
20.0 mm
62.83mm
13/16" (52/64")
0.8125"
20.64mm
2.553"
0.827"
21.0 mm
65.97mm
0.866"
22.0 mm
69.12mm
7/8" (56/64")
0.875"
22.22 mm
2.749"
0.906"
23.0 mm
72.26mm
15/16" (60/64")
0.9375"
23.81 mm
2.945"
0.945"
24.0 mm
75.40mm
0.984"
25.0 mm
78.54mm
Gauge or Fractional Inches
Decimal inches
Metric (mm)
Circumference aka (2 x π x Radius) aka (Diameter x π)
1" (64/64")
1.000"
25.40 mm
3.142" (think π)
1.024"
26.0 mm
81.68mm
1-1/16"
1.0625"
27.0 mm
3.338"= 84.82mm
1.102"
28.0 mm
87.96mm
1-1/8"
1.125"
28.6 mm
3.534"
1.142"
29.0 mm
91.11mm
1.181"
30.0 mm
94.25mm
1-3/16"
1.1875"
30.16 mm
3.731"
1.220"
31.0 mm
97.39mm
1-1/4"
1.250"
31.75 mm
3.927"
1.2598"
32.0 mm
100.53mm
1.299"
33.0 mm
103.67mm
1-5/16"
1.3125"
33.3 mm
4.123"
1.339"
34.0 mm
106.81mm
1-3/8"
1.375"
34.9 mm
4.3197"
1.378"
35.0 mm
109.96mm
1.417"
36.0 mm
113.10mm
1-7/16"
1.4375"
36.5 mm
4.516"
1.467"
37.0 mm
116.24mm
1.496"
38.0 mm
119.38mm
1-1/2"
1.500"
38.1 mm
4.712"
1.535"
39.0 mm
122.52mm
1-9/16"
1.5625"
39.7 mm
4.909"
1.575"
40.0 mm
125.66mm
1.614"
41.0 mm
128.81mm
1-5/8"
1.625"
41.3 mm
5.105"
1.654"
42.0 mm
131.95mm
1-11/16"
1.6875"
42.86 mm
5.301quot;
1.693"
43.0 mm
135.09mm
1.732"
44.0 mm
138.23mm
1-3/4"
1.750"
44.45 mm
5.498"
1.772"
45.0 mm
141.37mm
1.811"
46.0 mm
144.51mm
1-13/16"
1.8125"
46.04 mm
5.694"
1.850"
47.0 mm
147.66mm
1-7/8"
1.875"
47.6 mm
5.890"
1.8898"
48.0 mm
150.80mm
1.929"
49.0 mm
153.94mm
1-15/16"
1.9375"
49.2 mm
6.087"
1.969"
50.0 mm
157.08mm
2"
2.000"
50.8 mm
6.283" (2π)
Gauge or Fractional Inches
Decimal inches
Metric (mm)
Circumference aka (2 x π x Radius) aka (Diameter x π)
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