Piercing Gauge Sizes Explained: The Full Conversion Chart

The most common piercing gauges are 20g (0.81mm) for a first nostril piercing, 18g (1.02mm) for a standard earlobe or cartilage piercing, 16g (1.29mm) for many cartilage and some navel piercings, and 14g (1.63mm) for navel and nipple piercings. Gauge measures the thickness of the post itself, and the numbering runs backward from what most people expect: a lower gauge number means a thicker post, not a smaller one. The full chart below covers every size from a fine 20g down through 0000g.

In this article

• The full gauge conversion chart
• Why does a lower number mean a thicker post?
• Which gauge does each piercing typically use?
• Can I change my jewelry's gauge?
• How do I check the gauge of jewelry I already own?
• FAQ

The full gauge conversion chart

These are the standard Brown & Sharpe (American Wire Gauge) diameters that body jewelry sizing is based on. Commercially made jewelry can round slightly, so treat the millimeter figure as the precise reference and the fraction as a close approximation.

Why does a lower number mean a thicker post?

Gauge comes from the Brown & Sharpe wire gauge system, originally developed for measuring wire and sheet metal, not jewelry. That system numbers sizes by how many drawing passes it takes to pull a wire down to a given thickness, starting from a thick standard size. Fewer passes means a lower number and a thicker remaining wire; more passes means a higher number and a thinner one. Body jewelry simply inherited this industrial numbering system rather than inventing its own, which is why the scale feels backward if you've never run into it before.

Which gauge does each piercing typically use?

Standard gauges vary by placement, though a piercer will always confirm the exact size for your specific anatomy:

• Nostril: typically 18g to 20g.
• Septum: typically 14g to 16g.
• Earlobe: typically 18g to 20g for a standard piercing.
• Ear cartilage (helix, tragus, conch, and similar): typically 16g to 18g.
• Navel: typically 14g.
• Nipple: typically 14g.
• Tongue: typically 14g.

Our healing time chart covers how long each of these placements takes to heal once pierced at its standard gauge.

Can I change my jewelry's gauge?

Going up in gauge (to a thicker post) generally isn't something you can do by simply buying thicker jewelry. It typically requires a piercer to gradually stretch the piercing over weeks or months, which is a different process entirely from a standard healing timeline and carries its own risks if rushed. Going down to a thinner gauge than your piercing was originally done at usually isn't recommended either, since it can let the piercing shrink unevenly. The safest approach is simply buying jewelry that matches the gauge you were originally pierced at, which your piercer will tell you at the time.

How do I check the gauge of jewelry I already own?

The most reliable way is a caliper, the same tool used to measure wire and drill bits, since reading a post against a ruler is rarely precise enough to tell 16g from 18g at a glance. A jeweler or piercing studio will have one and can check a piece for you in seconds if you're not sure what you're holding. If you don't have access to a caliper, comparing the piece directly against a labeled reference piece in the same gauge from a known source is the next best option, since the visual difference between adjacent gauges is genuinely small.

Frequently asked questions

What gauge is a standard first earlobe piercing?

Most studios pierce a first earlobe at 18g or 20g. If you're not sure which yours was done at, check with your original piercer rather than guessing before buying new jewelry.

Is 16g bigger than 18g?

Yes. This is the part of the gauge system that trips people up: 16g (1.29mm) is thicker than 18g (1.02mm), since the number gets smaller as the post gets thicker, not the other way around.

Why do different charts show slightly different millimeter values for the same gauge?

Commercially manufactured jewelry sometimes rounds to the nearest common fraction of an inch rather than the exact Brown & Sharpe decimal value, which is why you may see 00g listed as both 9.27mm and an approximate 3/8" (9.53mm) depending on the source. The difference is small enough not to matter for fit in practice.

Can I use my own gauge measurement to buy jewelry from any brand?

Yes, gauge is a standardized measurement, so jewelry labeled 16g from any reputable brand should fit a piercing done at 16g, regardless of where you bought the original jewelry.