Spanner Size Conversion Chart
| Inches | Millimeters | Spanner |
| 0.250 | 1/4 AF | |
| 0.276 | 7mm | 7mm |
| 0.313 | 5/16 AF | |
| 0.315 | 8mm | 8mm |
| 0.344 | 11/32 AF; 1/8 Wworth | |
| 0.354 | 9mm | 9mm |
| 0.375 | 3/8 AF | |
| 0.394 | 10mm | 10mm |
| 0.433 | 11mm | 11mm |
| 0.438 | 7/16 AF | |
| 0.445 | 3/16 Wworth; 1/4 | |
| 0.472 | 12mm | 12mm |
| 0.500 | 1/2 AF | |
| 0.512 | 13mm | |
| 0.525 | 1/4 Wworth; 5/16 BSF | |
| 0.551 | 14mm | |
| 0.563 | 9/16 AF | |
| 0.591 | 15mm | |
| 0.600 | 5/16 Wworth; 3/8 BSF | |
| 0.625 | 5/8 AF | |
| 0.630 | 16mm | 16mm |
| 0.669 | 17mm | 17mm |
| 0.686 | 11/16 AF | |
| 0.709 | 18mm | 18mm |
| 0.710 | 3/8 Wworth; 7/16 BSF | |
| 0.748 | 19mm | 19mm |
| 0.750 | 3/4 AF | |
| 0.787 | 20mm | 20mm |
| 0.813 | 13/16 AF | |
| 0.820 | 7/16 Wworth; 1/2 BSF | |
| 0.826 | 21mm | 21mm |
| 0.866 | 22mm | 22mm |
| 0.875 | 7/8 AF | |
| 0.905 | 23mm | 23mm |
| 0.920 | 1/2 Wworth; 9/16 BSF | |
| 0.938 | 15/16 AF | |
| 0.945 | 24mm | 24mm |
| 0.984 | 25mm | 25mm |
| 1.000 | 1in AF | |
| 1.010 | 9/16 Wworth; 5/8 BSF | |
| 1.024 | 26mm | 26mm |
| 1.063 | 27mm | 1 1/16 AF; 27mm |
| 1.100 | 5/16 Wworth; 11/16 BSF | |
| 1.125 | 1 1/8 AF | |
| 1.181 | 30mm | 30mm |
| 1.200 | 11/16 Wworth; 3/4 BSF | |
| 1.250 | 1 1/4 AF | |
| 1.260 | 32mm | 32mm |
| 1.300 | 3/4 Wworth; 7/8 BSF | |
| 1.313 | 1 5/16 AF | |
| 1.390 | 13/16 Wworth; 15/16 BSF | |
| 1.417 | 36mm | 36mm |
| 1.418 | 1 7/16 AF | |
| 1.480 | 7/8 Wworth; 1in BSF | |
| 1.500 | 1 1/2 AF | |
| 1.575 | 40mm | 15/16 AF; 40mm exactly |
| 1.614 | 41mm | 41mm |
| 1.625 | 1 5/8 AF | |
| 1.670 | 1 in Wworth; 1 1/8 BSF | |
| 1.688 | 1 11/16 AF | |
| 1.811 | 46mm | 46mm |
| 1.813 | 1 13/16 AF | |
| 1.860 | 1 1/8 Wworth; 1 1/4 BSF | |
| 1.875 | 1 7/8 AF | |
| 1.969 | 50mm | 50mm |
| 2.000 | 2in AF | |
| 2.050 | 1 1/4 Wworth; 1 3/8 BSF | |
| 2.165 | 55mm | 55mm |
| 2.362 | 60mm | 60mm |