Gauge Size Converter | Convert gauge to mm and inches

Convert body jewellery gauge and AWG wire gauge to millimetres and inches. Includes full charts for both scales and what each size is commonly used for.


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Body jewellery gauge chart

Ear and body piercing sizes. The counter-intuitive part: a bigger gauge number means a thinner piece.

Gauge mm Inches Commonly used for
0.8 0.0315 Standard lobe and nostril piercings
1 0.0394 Lobe piercings, some cartilage
1.2 0.0472 Cartilage, eyebrow, lip
1.6 0.063 Industrial, septum, navel
2 0.0787 Early stretching
2.4 0.0945 Stretched lobes
3.2 0.126 Stretched lobes
4 0.1575 Stretched lobes
5 0.1969 Stretched lobes
6 0.2362 Stretched lobes
8 0.315 Large stretched lobes
9.3 0.3661 Last gauge before mm sizing

AWG wire gauge chart

American Wire Gauge diameters and cross-section areas, used for electrical wiring in North America.

Gauge mm Inches Area (mm2)
11.68 0.46 107.219
10.4 0.4096 85.029
9.27 0.3648 67.431
8.25 0.3249 53.475
7.35 0.2893 42.408
6.54 0.2576 33.631
5.83 0.2294 26.67
5.19 0.2043 21.151
4.62 0.1819 16.773
4.12 0.162 13.302
3.66 0.1443 10.549
3.26 0.1285 8.366
2.91 0.1144 6.634
2.59 0.1019 5.261
2.3 0.0907 4.172
2.05 0.0808 3.309
1.83 0.072 2.624
1.63 0.0641 2.081
1.45 0.0571 1.65
1.29 0.0508 1.309
1.15 0.0453 1.038
1.02 0.0403 0.823
0.91 0.0359 0.653
0.81 0.032 0.518
0.72 0.0285 0.41
0.64 0.0253 0.326
0.57 0.0226 0.258
0.51 0.0201 0.205
0.45 0.0179 0.162
0.4 0.0159 0.129
0.36 0.0142 0.102
0.32 0.0126 0.081
0.29 0.0113 0.064
0.25 0.01 0.051
0.23 0.0089 0.04
0.2 0.008 0.032
0.18 0.0071 0.025
0.16 0.0063 0.02
0.14 0.0056 0.016
0.13 0.005 0.013
0.11 0.0045 0.01
0.1 0.004 0.008
0.09 0.0035 0.006
0.08 0.0031 0.005

Why bigger gauge numbers mean smaller sizes

Gauge started as a manufacturing count, not a measurement. Wire was made by drawing it through a series of progressively smaller dies, and the gauge number recorded how many times it had been drawn. More passes meant thinner wire, so the number went up as the thickness went down. Body jewellery inherited the same scale, which is why 20g is a standard earring post and 00g is a very large stretched piercing.

Body jewellery sizes

Most ear piercings are done at 20g or 18g. Stretching then works down through the numbers, 16g, 14g, 12g and so on, until the scale runs out at 00g, after which sizes are quoted directly in millimetres or inches. The usual advice is to go one size at a time and wait several weeks between steps, because skipping sizes is what causes tearing and blowouts.

AWG wire sizes

American Wire Gauge follows a strict geometric rule rather than an arbitrary list: the diameter changes by a fixed ratio at every step, so going down six gauges roughly doubles the diameter and going down ten gauges multiplies the cross-section area by about ten. That is why current ratings scale so predictably. Beyond gauge 1 the scale continues as 0, 00, 000 and 0000, usually written 1/0 through 4/0.

Worth knowing

  • A gauge number on its own is ambiguous. Jewellery gauge and wire gauge are different scales, and sheet metal gauge is different again.
  • Once body jewellery passes 00g, the scale stops and sizes are given in millimetres, so the next common size after 00g is 11 mm.
  • For wire, dropping three gauge numbers roughly doubles the cross-section area, and dropping six roughly doubles the diameter.
  • Jewellery is sold by the actual bar thickness, so measure with callipers rather than guessing from a photo.
  • Gauge numbers are written with the larger sizes as 0, 00, 000, sometimes shown as 1/0, 2/0, 3/0.

Frequently asked questions

14 gauge is 1.6 mm, which is 0.0625 inches or one sixteenth of an inch. It is a common size for industrial piercings, septum jewellery and stretched lobes at an early stage. Enter any gauge above to see its exact diameter.

Because the number originally counted manufacturing steps rather than size. Wire was drawn through successively smaller dies, and the gauge recorded how many passes it took, so more passes meant thinner wire and a higher number. Body jewellery adopted the same scale, so 20g is thin and 00g is thick.

The gauge scale ends at 00g, which is 9.3 mm. After that, sizes are quoted directly in millimetres or inches, so the next common step is 10 mm, then 11 mm and upward. That is why larger plugs are always advertised by their millimetre size rather than a gauge number.

Most standard earlobe piercings are made at 20g (0.8 mm) or 18g (1.0 mm), and typical earring posts are in that range. Cartilage piercings are often 16g (1.2 mm), and nose studs are usually 20g or 18g.

For body jewellery the steps are not evenly spaced, but each one is roughly a 20 to 25 percent increase in diameter. That is why piercers advise waiting several weeks between sizes: the tissue has to accommodate a noticeably larger piece each time, and skipping a step is the usual cause of tearing.

American Wire Gauge is the standard scale for electrical wire diameters in North America. Like jewellery gauge, smaller numbers mean thicker wire. It follows a strict geometric progression, so dropping six gauge numbers roughly doubles the diameter and dropping ten multiplies the cross-section area by about ten.

They share an origin and the same direction, smaller number means thicker, but the actual sizes differ, so you cannot read one off the other. This converter keeps them as two separate scales for that reason. Sheet metal gauge is a third, unrelated scale again.

Measure the thickness of the jewellery itself with digital callipers, in millimetres, then enter that figure above. Do not measure the hole, which is always slightly larger and changes shape, and do not judge from a photo. If your reading falls between two gauges, the converter shows the nearest.

What size is a gauge in mm?

For body jewellery, 20g is 0.8 mm, 14g is 1.6 mm and 00g is 9.3 mm. The scale runs backwards, so a bigger number means a thinner piece, and it stops at 00g after which sizes are quoted straight in millimetres. This tool also converts AWG wire gauge, which is a separate scale.