| Length (Inches) | Millimeter Equivalent |
| 5/16 | 7.969 |
| 3/8 | 9.563 |
| 7/16 | 11.156 |
| 1/2 | 12.750 |
| 5/8 | 15.88 |
| 3/4 | 19.04 |
| 7/8 | 22.22 |
| 1 | 25.40 |
The most common size and gauge for a navel piercing is 1.6mm (14 gauge) and eitehr 6mm, 8mm, 10mm or 12mm in Length.
This does not mean that it is the correct size for you,but it is the most common size and used in about 85% of all navel piercings.You can use the conversion charts below to give you an idea of what gauge your current jewelry is.
| Gauge | Inch Equivalent | Millimeter Equivalent |
| 20 | .032 | 0.813 |
| 18 | .040 | 1.000 |
| 16 | .051 | 1.290 |
| 14 | .064 | 1.629 |
| 12 | .081 | 2.052 |
| 10 | .102 | 2.588 |
| 8 | .128 | 3.264 |
| 6 | .162 | 4.111 |
| 4 | .204 | 5.189 |
| 2 | .257 | 6.543 |
| 0 | .324 | 8.230 |
| 00 | .364 | 9.246 |
| Length (Inches) | Millimeter Equivalent |
| 5/16 | 7.969 |
| 3/8 | 9.563 |
| 7/16 | 11.156 |
| 1/2 | 12.750 |
| 5/8 | 15.88 |
| 3/4 | 19.04 |
| 7/8 | 22.22 |
| 1 | 25.40 |