Earring gauge to millimeters, and what size comes next

The chart

Two millimeter columns because two systems are in use. The gauge scale is American Wire Gauge, and its exact diameters are the odd numbers in the third column. Body jewelry makers round them to the tidy numbers in the second column, and nearly every plug or barbell sold as 16g is actually 1.2 mm. The difference matters once: a 00g piece is 10 mm by the jewelry convention but 9.27 mm by AWG, so after 00g everyone switches to inches or millimeters and stops arguing.

Why the numbers run backwards

Gauge comes from wire drawing. A number was the count of passes through successively smaller dies needed to make the wire, so more passes meant thinner wire and a higher number. Jewelry inherited the scale from the wire it was made of, which is also why the steps are not equal: each gauge is about 12% thinner than the one before, so the jump from 20g to 18g is 0.2 mm and the jump from 0g to 00g is 2 mm. That last step is the one people find hardest, and half sizes exist for it.

Which piercings use which gauge

Lobes

Pierced at 18g or 20g in studios, 20g with a piercing gun. Standard earrings fit either; an 18g hole accepts 20g posts loosely and 16g with a slight stretch.

Cartilage: helix, tragus, conch

Usually 16g, sometimes 18g. Cartilage does not stretch like a lobe and is not meant to; jewelry is changed, not sized up.

Nose

18g or 20g for nostrils, 16g for septums. Nose studs sold as 20g fit most nostril piercings; a 22g stud will fall out of an 18g hole.

Navel, eyebrow, tongue, industrial

14g is the standard for navel, tongue and industrial bars; eyebrows are 16g. These are structural sizes chosen so the bar does not migrate, not stretching sizes.

Measuring your gauge at home

Measure the jewelry, not the hole

Take out a piece that fits comfortably and measure the post or the wearable part of the plug, never the decorative end. A digital caliper reading to 0.1 mm is the right tool and costs about as much as a pair of plugs; place the jaws across the post, read the millimeters, and match them to the nominal column above. Round to the nearest listed size: 1.1 mm is a 16g, 1.5 is a 14g.

Without a caliper

Print the circle chart above at 100%, check the scale with a ruler, and stand the post on the circles: the one it covers exactly is its gauge. For plugs, lay the wearable section across the circles. Comparing against a known piece, such as a standard 20g stud, gets you within one size.

What not to do

Do not measure the hole with a taper or by forcing jewelry in; a piercing has no fixed size, it takes the size of what it wears, and pushing bigger jewelry through is a stretch whether you call it one or not.

Gold and gauges

Ordinary gold earring posts are 20g and sometimes 22g (0.6 mm), and 14k is the usual choice because it is hard enough not to bend when the butterfly back is pushed on. For fresh piercings, nickel-free alloys and implant-grade titanium are the standard recommendation; 14k yellow gold is generally well tolerated, while white gold alloyed with nickel is the common cause of the itching people blame on gold. Solid gold plugs above about 2g get expensive quickly because weight rises with the square of the diameter; most gold-look plugs at large sizes are gold-plated steel or wood with gold ends.

Stretching, and where it stops being reversible

The rules

One gauge step at a time. Wait until the tissue is fully settled before the next step, at least a month at small sizes and longer as the size grows; the lobe should be soft, unmarked and not sore. Lubricate, use a taper or tape wrapping for the step, and stop at the first sign of a tear or a thin white ring, which is a blowout starting. Skipping sizes is how lobes thin and scar.

Materials by stage

Fresh stretches want smooth, non-porous, single-piece jewelry: implant-grade steel, titanium or glass. Once healed, wood, stone, horn and silicone are comfortable and light, and wood in particular breathes and cuts down on odor, which is why large-gauge wearers tend to move to it. Acrylic and unknown-alloy plugs are the usual cause of irritation at any size.

The point of no return

Lobes stretched to about 2g (6 mm) and left empty usually shrink back to something close to a normal piercing over months. Beyond 0g the odds of a full return drop fast, and above 1/2 inch the lobe will not close without surgery. Decide before 2g whether you want the option back.

Questions people ask