| Metric Size | U.S. Size | Comments | Metric to U.S. Ratio |
| 7mm | 5/16" | [Extremely loose] | 113% |
| 8mm | 5/16" | [Tight] | 99% |
| 9mm | 11/32" | [Too tight unless head is damaged] | 97% |
| 10mm | 7/16" | [Extremely loose] | 111% |
| 11mm | 7/16" | [Very good] | 101% |
| 12mm | 1/2" | [Very loose] | 106% |
| 13mm | 1/2" | [Too tight unless head is damaged] | 98% |
| 14mm | 9/16" | [Loose] | 102% |
| 15mm | 19/32" | [Very good] | 101% |
| 17mm | 11/16" | [Loose] | 103% |
| 19mm | 3/4" | [Perfect] | 100% |
| 22mm | 7/8" | [Slightly loose] | 101% |
| 25mm | 1" | [Loose] | 102% |
| 27mm | 1-1/16" | [Perfect] | 100% |
| 30mm | 1-3/16" | [Slightly loose] | 101% |
| 36mm | 1-7/16" | [Slightly loose] | 101% |