So many sizes! How do you know what is what??? Here is some help. It is our handy Metric, English, and Gauge (AWG) conversion chart. If you need a 21 gauge headpin and want to know what size that is in mm or inches just take a look here.
| American Gauge (AWG) | Inches (in) | Millimeters (mm) |
| 12 | 0.081 | 2.052 |
| 14 | 0.064 | 1.628 |
| 16 | 0.051 | 1.291 |
| 18 | 0.040 | 1.024 |
| 20 | 0.032 | 0.812 |
| 21 | 0.029 | 0.723 |
| 22 | 0.025 | 0.644 |
| 24 | 0.02 | 0.511 |
| 26 | 0.016 | 0.405 |
| 28 | 0.013 | 0.321 |
| 30 | 0.010 | 0.255 |
| 32 | 0.008 | 0.200 |
| 34 | 0.006 | 0.160 |
| 36 | 0.005 | 0.130 |
Now let's say you want a 2 inch long semiprecious gemstone bead but you have no idea what size that is in millimeters(mm). Just take a look here. The entire beading world outside the US measures in metric so this conversion chart should help.
| Inches (in) or (") | Millimeters (mm) |
| 0.04 | 1 |
| 0.08 | 2 |
| 0.12 | 3 |
| 0.16 | 4 |
| 0.20 | 5 |
| 0.24 (1/4 inch) | 6 |
| 0.28 | 7 |
| 0.31 | 8 |
| 0.35 | 9 |
| 0.39 | 10 |
| 0.43 | 11 |
| 0.47 | 12 |
| 0.51 (1/2 inch) | 13 |
| 0.55 | 14 |
| 0.59 | 15 |
| 0.63 | 16 |
| 0.67 | 17 |
| 0.71 | 18 |
| 0.75 (3/4 inch) | 19 |
| 0.79 | 20 |
| 0.83 | 21 |
| 0.87 | 22 |
| 0.91 | 23 |
| 0.94 | 24 |
| 0.98 (1 inch) | 25 |
| 1.02 | 26 |
| 1.06 | 27 |
| 1.10 | 28 |
| 1.14 | 29 |
| 1.18 | 30 |
| 1.22 | 31 |
| 1.26 (1-1/4 inch) | 32 |
| 1.30 | 33 |
| 1.34 | 34 |
| 1.38 | 35 |
| 1.42 | 36 |
| 1.46 | 37 |
| 1.50 (1-1/2 inch) | 38 |
| 1.54 | 39 |
| 1.57 | 40 |
| 1.61 | 41 |
| 1.65 | 42 |
| 1.70 | 43 |
| 1.73 (1-3/4") | 44 |
| 1.77 | 45 |
| 1.81 | 46 |
| 1.85 | 47 |
| 1.89 | 48 |
| 1.93 | 49 |
| 1.97 (2 inch) | 50 |
