Gauge Size Converter
Turn a piercing gauge into millimetres and inches, or measure a piece of jewelry and find the nearest standard gauge.
Read the size before you buy
Gauge is the single most-confused number in body jewelry: the scale runs backwards, and studios in different countries quote thickness in gauge or in millimetres. Converting once removes the guesswork, so the 16g listing and the 1.2 mm listing read as the same bar.
Once you know the gauge, size the rest of the piece with the Jewelry Size Calculator for post length, or the Ring Diameter Calculator for a hoop. Planning to go bigger? The Gauge Stretching Planner maps the steps.
Frequently Asked Questions
Why is a higher gauge number a thinner bar?
Gauge is a wire-thickness scale inherited loosely from wire-manufacturing systems, where the number counts how many times the wire was drawn thinner. So a bigger number means a thinner bar: a 20g nostril stud is 0.8 mm, while a 0g plug is 8 mm. It feels backwards at first, which is exactly why converting to millimetres makes sizing so much clearer.
What is the difference between gauge and length?
Gauge is the thickness of the bar or wire; length (or, for a ring, internal diameter) is how long or wide the piece is. A '16g 8mm labret' is 1.2 mm thick and 8 mm long. This tool handles the thickness — use the jewelry size calculator for post length and the ring diameter calculator for hoop sizing.
My jewelry measured between two gauges — which is it?
Gauges are fixed standard sizes, so a caliper reading between two of them just means measuring tolerance or wear. Enter the millimetre value and the converter snaps it to the closest standard gauge and shows how far off it was. If it sits almost exactly between two sizes, the thinner (higher-number) gauge is usually the safer assumption for fit.
Are these millimetre values exact?
They are the industry-standard body-jewelry chart values, which are rounded conventions rather than the raw wire-gauge formula — 14g is quoted as 1.6 mm, for example. Reputable jewelry is made to these standards, but manufacturing tolerances mean a real piece can vary slightly. When in doubt, measure the actual jewelry with calipers.
Standard body-jewelry chart values; real jewelry can vary within manufacturing tolerances. Measure the actual piece when a precise fit matters.