Convert ear gauge and body jewelry sizes, from fine 20g studs to 00g and inch plugs up to 2", into millimetres and inches, or measure in mm and find the gauge. The printable chart shows every size as a true-scale circle.
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Convert
Inner diameter of the piercing or outer diameter of the jewelry
Enter your values to see the result.
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How to use the Ear Gauge to MM Converter
Choose the direction: gauge to mm and inches, or a measured size to gauge.
Pick the gauge or type the size in mm or inches.
Press Convert to see the size, fraction and neighbouring sizes.
Print the chart at 100% scale to compare jewelry against true-size circles.
Gauge sizes at a glance
Gauge
mm
Inches
Typical use
20g
0.8
0.032
Standard earrings, nose studs
18g
1.0
0.040
Earrings, nose rings, cartilage
16g
1.2
0.047
Common piercing size for lobes, helix, tragus, lip
14g
1.6
1/16 (0.063)
Navel, tongue, industrial; first stretch for many
12g
2.0
5/64 (0.079)
Early stretched lobes
8g
3.2
1/8 (0.125)
Small stretched lobes
2g
6–6.5
1/4 (0.250)
Medium plugs
0g
8
5/16 (0.313)
Popular plug size
00g
9.5–10
3/8 (0.375)
Last numbered gauge
1/2"
12.7
0.500
Large plugs and tunnels
1"
25.4
1.000
Very large plugs
Why sizes differ between shops
Gauge sizes started with wire gauges, while plugs above 00g are measured in inches in the US and in millimetres elsewhere. Brands round the conversions differently: 2g can be 6 mm or 6.5 mm, 00g can be 9.5 mm or 10 mm and 1/2" can be 12 mm, 12.7 mm or 13 mm. When buying, compare the millimetre figure rather than the gauge name, and stay with one sizing system for a set of plugs.
Steps grow with size. Going from 14g to 12g adds 0.4 mm, but 0g to 00g adds about 2 mm, a 25% increase. Many people use half sizes (for example 9 mm) between the bigger steps.
Printing the chart. Print at 100% (no "fit to page") and check that the 25 mm circle measures 25 mm with a ruler before relying on it.
Measure jewelry, not the hole. A fresh piercing can feel tighter than the jewelry you wear, so use the size of jewelry that fits comfortably.
Frequently asked questions
What is 0g in mm?
0g is 8 mm (5/16 inch). 00g is the next size up at about 10 mm (3/8 inch, which is exactly 9.5 mm), and 2g below it is 6–6.5 mm.
What gauge is a normal earring?
Most standard earrings for lobe piercings are 20g (0.8 mm) or 18g (1.0 mm). Piercing studios usually pierce lobes at 16g (1.2 mm) or 14g (1.6 mm), and cartilage often at 16g.
Why does a smaller gauge number mean a bigger size?
Body jewelry gauges come from wire gauges, where higher numbers are thinner wire. So 20g is very thin and the numbers shrink as the size grows until 0g and 00g, after which sizes are given in inches or millimetres.
Is 00g 9.5 mm or 10 mm?
Both are sold. 3/8 inch is exactly 9.53 mm, and many metric brands round 00g up to 10 mm. If your jewelry is tight, check whether it is labelled in inches or mm, because mixing the two can give a 0.5 mm difference.
How do I measure my ear gauge size?
Measure the outside diameter of the jewelry you wear comfortably, not the flare, with calipers or a ruler in millimetres, then use the mm → gauge mode. For tunnels, the wearable size is the outer diameter of the tube.
How should ear stretching be done safely?
Go up one size at a time, use smooth, body-safe jewelry, and wait several weeks or longer between sizes. Never force a size; pain or bleeding means you are going too fast. A professional piercer can advise for your ears.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.