Ga
Body jewelry and needles tend to be identified by their gauge, using the Browne & Sharpe or American wire gauge system, at least in North America (many other regions simply use metric sizing). The larger the gauge, the smaller the diameter.
Overview
The diameter of an n gauge wire (commonly written "nga"), is defined to be:
For larger gauges written as m zeros, let n = −(m − 1). That is, 0ga = 0, 00ga = −1, etc.
Body jewelry is measured using calipers, Vernier Gauge, a Micrometer or a Gauge wheel by its outer diameter. Needles, in the medical sense (including Play piercing needles), are measured by the inner diameter of the tube (so a 16ga needle will actually have an outer diameter of about 14ga), whereas piercing needles are always measured by their outer diameter. The body jewelry industry uses mostly even gauges between 18 and 00ga, although odd gauges are seen from time to time, usually when non-North American jewelry is being imported. The difference in diameter between gauges two units apart is about 26%. Larger sizes are usually referred to by their measured size.
Common sizes
Please note that some of the fractional sizes below have been rounded to their closest match:
| Gauge | Fractional size | Inches | Millimeters |
|---|---|---|---|
| 1/32" | 0.031" | 0.794mm | |
| 18ga | 0.040" | 1.024mm | |
| 3/64" | 0.047" | 1.191mm | |
| 16ga | 0.051" | 1.291mm | |
| 14ga | 1/16" | 0.064" | 1.628mm |
| 12ga | 5/64" | 0.081" | 2.053mm |
| 3/32" | 0.094" | 2.381mm | |
| 10ga | 1/10" | 0.102" | 2.588mm |
| 8ga | 1/8" | 0.128" | 3.264mm |
| 5/32" | 0.156" | 3.969mm | |
| 6ga | 0.162" | 4.115mm | |
| 3/16" | 0.178" | 4.763mm | |
| 4ga | 13/64" | 0.204" | 5.189mm |
| 2ga | 1/4" | 0.258" | 6.544mm |
| 0ga | 5/16" | 0.325" | 8.251mm |
| 00ga | 0.365" | 9.266mm | |
| 3/8" | 0.375" | 9.525mm | |
| 000ga | 0.410" | 10.41mm | |
| 7/16" | 0.438" | 11.11mm | |
| 0000ga | 15/32" | 0.460" | 11.68mm |
| 1/2" | 0.5" | 12.7mm | |
| 00000ga | 33/64" | 0.517" | 13.1mm |
| 9/16" | 0.563" | 14.3mm | |
| 5/8" | 0.625" | 15.9mm | |
| 11/16" | 0.688" | 17.5mm | |
| 3/4" | 0.75" | 19.1mm | |
| 13/16" | 0.813" | 20.6mm | |
| 7/8" | 0.875" | 22.2mm | |
| 15/16" | 0.9375" | 23.8mm | |
| 1" | 1.0" | 25.4mm | |
| 1 1/16" | 1.0625" | 26.9875mm | |
| 1 1/8" | 1.125" | 28.575mm | |
| 1 3/16" | 1.1875" | 30.1625mm | |
| 1 1/4" | 1.25" | 31.75mm | |
| 1 5/16" | 1.3125" | 33.3375mm | |
| 1 3/8" | 1.375" | 34.925mm | |
| 1 7/16" | 1.4375" | 36.5125mm | |
| 1 1/2" | 1.5" | 38.1mm | |
| 1 9/16" | 1.5625" | 39.6875mm | |
| 1 5/8" | 1.625" | 41.275mm | |
| 1 3/4" | 1.75" | 44.45mm | |
| 1 7/8" | 1.875" | 47.625mm | |
| 2" | 2" | 50.8mm |
Most body piercings are initially performed at between 14ga and 10ga depending on the piercing, but that is far from a hard rule and there are many arguments debating the subject of initial gauge size.
Gauge sizes do exist larger, but past 00ga people tend to use fractional imperial sizing (ie. "half inch").
Size equivalents
As far as the gauges of common household objects, below is a (vaguely accurate) list started by RAB's Lish:
| Gauge | Objects |
|---|---|
| 16ga | thumbtack tip, big safety pin. |
| 14ga | metal coat hanger, bike spoke, wire from triangular business clamp. |
| 12ga | wire hanger, spaghetti. |
| 10ga | round toothpick, q-tip shaft, small bamboo skewer. |
| 8ga | fire extinguisher pin, #5 crochet hook, lightsaber handles from Star Wars lego sets, small pilot lock, coffee swizzles, ink cartridge. |
| 6ga | juice box straw, lightbrite peg, mini-glowstick, Rold Gold pretzel stick, heroin-style medical tubing, round boot lace, lollipop stick. |
| 4ga | pilot stylus, large bamboo skewer, chopstick. |
| 2ga | drinking straw, power cord for N64, Bic automatic pencil, crayola colored pencil, yellow pipette tip, crossbow bolt, no.2 pencil. |
| 0ga | Bic round stic, candy cane, round chopsticks, Master Lock shackle, PCR tube, blue pipette tip, plastic clothes hanger. |
| 00ga | Bic round stic cap, 1/4" male headphone jack, lego person's head, fat crayons, American lock company #5200 shackle, beaded Christmas garland, Papermate Gel Roller pen. |
| 000ga | Sharpie marker body, wooden spoon handle, 1/4" female headphone jack, A/V adaptor plug head from Sony Playstation. |
| 0000ga | Sharpie marker cap, mini one-use hydrating shampoo/conditioner bottle, Eppendorf reaction vial |