12 mmvs.1/2″
1/2″ is exactly 12.7 mm, so the difference is 0.7 mm. Treating them as identical can matter for fit.
Gauge ↔ millimeters ↔ inches
Ear gauge size chart, without the rounded-label guesswork.
Type any common size, see the exact conversion and customary jewelry label, then compare or calibrate the circle to your screen.
Quick sizes
Gauge · nominal diameter
00g
- Diameter
- 10 mm nominal
- Exact inches
- 0.3937 in
- Nearest 1/64″
- 25/64″ nearest 1/64″
- Common label
- 3/8″
- Cross-section
- 78.54 mm²
00g is not a single universal millimeter value. Product listings and charts commonly place it around 9–10 mm; this tool uses 10.0 mm as the common nominal value.
Chart position: 0g · 00g · 11 mm. This is a measurement sequence, not a recommended jump.
1/2″
12.7 mm
0.5 in exact
- Diameter change
- +2.7 mm
- Diameter %
- +27%
- Area change
- +48.1 mm²
- Area %
- +61.3%
Compared with 00g, 1/2″ is 2.7 mm wider and has 61.3% more cross-sectional area. This describes geometry, not a recommended jump.
Outer diameter
Size on screen
Jewelry view
Approximate scale — calibrate this screen for a physical-size view.
Calibrate screen
Runs in your browser
Exact math + common labels
1:1 print verification
Complete reference
Ear gauge conversion chart
Gauge rows use common nominal body-jewelry diameters. Fraction rows are mathematically exact; the “often sold as” column shows customary rounded metric labels rather than pretending they are identical.
| Chart label | Millimeters | Exact inches | Common paired label | Important note | Use in converter |
|---|---|---|---|---|---|
| 20g | 0.8 mm nominal | 0.0315 in | 1/32″ | Fine common jewelry size | |
| 18g | 1.0 mm nominal | 0.0394 in | 5/128″ | Common earlobe piercing size | |
| 16g | 1.2 mm nominal | 0.0472 in | 3/64″ | Fraction is customary shorthand | |
| 14g | 1.6 mm nominal | 0.0630 in | 1/16″ | Confirm the product’s stated mm | |
| 12g | 2.0 mm nominal | 0.0787 in | 5/64″ | Nominal body-jewelry label | |
| 10g | 2.4 mm nominal | 0.0945 in | 3/32″ | 3/32″ is exactly 2.381 mm | |
| 8g | 3.0 mm nominal | 0.1181 in | 1/8″ | 1/8″ is exactly 3.175 mm | |
| 6g | 4.0 mm nominal | 0.1575 in | 5/32″ | 5/32″ is exactly 3.9688 mm | |
| 4g | 5.0 mm nominal | 0.1969 in | 3/16″ | 3/16″ is exactly 4.7625 mm | |
| 2g | 6.0 mm nominal | 0.2362 in | 1/4″ | 1/4″ is exactly 6.35 mm | |
| 1g | 7.0 mm nominal | 0.2756 in | 9/32″ | Useful intermediate size; not stocked by every maker | |
| 0g | 8.0 mm nominal | 0.3150 in | 5/16″ | 5/16″ is exactly 7.9375 mm | |
| 00g | 10.0 mm common nominal | 0.3937 in | 3/8″ | Often varies around 9–10 mm; verify the maker | |
| 7/16″ | 11.1125 mm exact | 0.4375 in | 11 mm | 11 mm is 0.1125 mm smaller | |
| 1/2″ | 12.7000 mm exact | 0.5000 in | 12 or 13 mm | 12 mm is not exactly 1/2″ | |
| 9/16″ | 14.2875 mm exact | 0.5625 in | 14 mm | 14 mm is 0.2875 mm smaller | |
| 5/8″ | 15.8750 mm exact | 0.6250 in | 16 mm | Very close; 16 mm is 0.125 mm larger | |
| 11/16″ | 17.4625 mm exact | 0.6875 in | 18 mm | 18 mm is 0.5375 mm larger | |
| 3/4″ | 19.0500 mm exact | 0.7500 in | 19 mm | Near-equivalent; difference is 0.05 mm | |
| 13/16″ | 20.6375 mm exact | 0.8125 in | 20 mm | 20 mm is 0.6375 mm smaller | |
| 7/8″ | 22.2250 mm exact | 0.8750 in | 22 mm | 22 mm is 0.225 mm smaller | |
| 15/16″ | 23.8125 mm exact | 0.9375 in | 24 mm | 24 mm is 0.1875 mm larger | |
| 1″ | 25.4000 mm exact | 1.0000 in | 25 mm | 25 mm is 0.4 mm smaller | |
| 1 1/16″ | 26.9875 mm exact | 1.0625 in | 27 mm | Near-equivalent; difference is 0.0125 mm | |
| 1 1/8″ | 28.5750 mm exact | 1.1250 in | 28 or 29 mm | Check the maker’s exact millimeters | |
| 1 3/16″ | 30.1625 mm exact | 1.1875 in | 30 mm | 30 mm is 0.1625 mm smaller | |
| 1 1/4″ | 31.7500 mm exact | 1.2500 in | 32 mm | 32 mm is 0.25 mm larger | |
| 1 5/16″ | 33.3375 mm exact | 1.3125 in | 33 mm | 33 mm is 0.3375 mm smaller | |
| 1 3/8″ | 34.9250 mm exact | 1.3750 in | 35 mm | Near-equivalent; difference is 0.075 mm | |
| 1 7/16″ | 36.5125 mm exact | 1.4375 in | 36 mm | 36 mm is 0.5125 mm smaller | |
| 1 1/2″ | 38.1000 mm exact | 1.5000 in | 38 mm | Near-equivalent; difference is 0.1 mm | |
| 1 9/16″ | 39.6875 mm exact | 1.5625 in | 40 mm | 40 mm is 0.3125 mm larger | |
| 1 5/8″ | 41.2750 mm exact | 1.6250 in | 41 mm | 41 mm is 0.275 mm smaller | |
| 1 11/16″ | 42.8625 mm exact | 1.6875 in | 43 mm | 43 mm is 0.1375 mm larger | |
| 1 3/4″ | 44.4500 mm exact | 1.7500 in | 44 mm | 44 mm is 0.45 mm smaller | |
| 1 13/16″ | 46.0375 mm exact | 1.8125 in | 46 mm | Near-equivalent; difference is 0.0375 mm | |
| 1 7/8″ | 47.6250 mm exact | 1.8750 in | 48 mm | 48 mm is 0.375 mm larger | |
| 1 15/16″ | 49.2125 mm exact | 1.9375 in | 49 mm | 49 mm is 0.2125 mm smaller | |
| 2″ | 50.8000 mm exact | 2.0000 in | 50 or 51 mm | Check the maker’s exact millimeters |
Why four decimals? They expose real unit differences. Jewelry manufacturing tolerances can still be larger than the displayed mathematical difference, so use a caliper and the product specification for a purchase decision.
Measure what you own
How to measure plugs and tunnels
The useful number is the wearable outside diameter, not the widest flare. A digital caliper is the clearest method; a verified print chart is a backup, not a substitute for a precise product specification.
-
01
Measure the wearable section
Place the caliper jaws across the straight section that sits in the piercing. Do not measure saddle or flare width.
-
02
Read millimeters first
Record the diameter to the precision your caliper supports. Millimeters avoid many rounded fraction-label mismatches.
-
03
Convert, then confirm the listing
Use the tool to find familiar labels, but buy by the seller’s stated millimeter diameter and tolerance when fit matters.
Exact math vs. jewelry shorthand
Why two charts can “disagree” and both look familiar
The fixed conversion
1 inch=25.4 mm
That equation never changes. The mismatch comes from customary product labels that round a metric diameter to a nearby fraction—or a fraction to a nearby whole millimeter.
19 mmvs.3/4″
3/4″ is exactly 19.05 mm. The difference is only 0.05 mm, but the product specification is still the authority.
00gis notone universal mm
Charts and products often place 00g around 9–10 mm. This site uses 10 mm as a common nominal reference and flags the variation every time.
The jump is not only the diameter
A small-looking diameter change can be a much larger area change.
Cross-sectional area grows with the square of diameter: area = π × (diameter ÷ 2)². That is why the comparison tool reports both measurements instead of showing only the next row in a chart.
Geometry explains the size difference; it does not decide whether a change is appropriate for your tissue, jewelry, healing history or timing.
- 0g nominal
- 8 mm · 50.27 mm²
- 00g nominal
- 10 mm · 78.54 mm²
- Diameter
- +25%
- Area
- +56.25%
Measurement tool, not a stretching prescription
Use dimensions to identify jewelry—not to override warning signs.
The Association of Professional Piercers advises that a knowledgeable piercer can evaluate anatomy and jewelry, and that severe discomfort, bleeding or tearing means tissue is being overstressed. It also notes that metric increments can make size changes more gradual and cautions against using tapered jewelry as a do-it-yourself stretching tool.
Stop and seek an experienced piercer or appropriate medical care when there is significant pain, bleeding, tearing, persistent swelling, weeping, worsening inflammation, suspected infection or other tissue damage.
Read the APP stretching guidanceQuick answers
Common ear gauge size questions
What size is 00g in millimeters?
There is no single universal value. Many body-jewelry charts and products use roughly 9–10 mm. This converter uses 10.0 mm as the common nominal reference and tells you to verify the manufacturer’s stated diameter.
Is 12 mm the same as 1/2 inch?
No. One half inch is exactly 12.7 mm. Retailers often pair 12 mm or 13 mm with the 1/2″ label, so use the exact millimeter specification when fit matters.
What size comes after 00g?
Beyond 00g, labels usually switch to millimeters or fractions. A chart may show 11 mm next, but that is only the next measurement reference—not a personal recommendation about timing or size change.
How can the circle show actual size on my screen?
Choose Actual, then calibrate the card outline against a standard ID-1 bank or identification card that is 85.60 × 53.98 mm. Recheck after changing browser zoom, display scaling, monitor or device.
Can I print the circles at one-to-one scale?
Yes. Use Print / save PDF and select 100% or Actual Size—not Fit to page. Measure both the 50 mm and 2 inch verification bars before using the printed circles.
Should I include the flare when measuring a plug?
No. Measure the wearable outside diameter of the section that sits in the piercing. Flared ends are intentionally wider and do not represent the labeled wearable size.
Transparent method
How this chart calculates and labels sizes
Reviewed July 27, 2026
Exact conversion
Inches = millimeters ÷ 25.4. Millimeters = inches × 25.4. Decimal values remain exact to the shown precision; nearest fractions are clearly labeled as nearest rather than silently substituted.
Gauge labels
Gauge rows use common body-jewelry nominal diameters. They are product-language references, not a claim that every maker’s piece has zero tolerance or that every chart uses the same 00g value.
Comparison
Area is calculated as π × (diameter ÷ 2)². Percentage change uses the first selected size as the baseline, so reversing the comparison changes the percentage.
Actual-size display
Before calibration, the app uses the CSS reference of 96 pixels per inch and labels the result approximate. Calibration stores only a local pixels-per-millimeter value and display hints.
Primary references and cross-checks
- Association of Professional Piercers — Stretching General professional guidance and limitations
- ISO/IEC 7810 identification-card dimensions 85.60 × 53.98 mm screen-calibration reference
- Plug Your Holes — Ear Gauge Sizes Common body-jewelry nominal labels
- Omerica Organic — Ear Gauge Sizing Manufacturer-label variation and larger-size cross-check
Source selection does not imply endorsement. Report a conversion or accessibility issue through the site owner’s published contact channel when available.