| US Women's Size | US Men's Size | Birkenstock® |
| 4 - 4.5 | 2 - 2.5 | 35 |
| 5 - 5.5 | 3 - 3.5 | 36 |
| 6 - 6.5 | 4 - 4.5 | 37 |
| 7 - 7.5 | 5 - 5.5 | 38 |
| 8 - 8.5 | 6 - 6.5 | 39 |
| 9 - 9.5 | 7 - 7.5 | 40 |
| 10 - 10.5 | 8 - 8.5 | 41 |
| 11 - 11.5 | 9 - 9.5 | 42 |
| 12 - 12.5 | 10 - 10.5 | 43 |
| 13 - 13.5 | 11 - 11.5 | 44 |
| 14 - 14.5 | 12 - 12.5 | 45 |
| 15 - 15.5 | 13 - 13.5 | 46 |
| 16 - 16.5 | 14 - 14.5 | 47 |
| 15 - 15.5 | 48 |
| Birkenstock® Men's and Women's Widths | US Width |
| Regular | C-D |
| Narrow | A- B |
| US Kids Size | Birkenstock® |
| 7 - 7.5 | 24 |
| 8 | 25 |
| 8.5 | 26 |
| 9 - 9.5 | 27 |
| 10 - 10.5 | 28 |
| 11 - 11.5 | 29 |
| 12 - 12.5 | 30 |
| 13 - 13.5 | 31 |
| 1 - .5 | 32 |
| 2 - 2.5 | 33 |
| 3 - 3.5 | 34 |