SAE and Metric Wrench and Socket Size Reference
In combined wrench sets, manufacturers often provide a single wrench for sizes that are very close (typically within 0.05 mm or less) to avoid redundancy.
Common Wrench Sizes
- Standard (SAE): Common sizes in inches: 1/4, 5/16, 11/32, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4, 13/16, 7/8, 15/16, 1, 1-1/16, 1-1/8, 1-1/4.
- Metric: Common sizes in mm: 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 24, 27, 30, 32.
combined sets where one wrench serves both sizes:
- 19 mm and 3/4 inch (19.05 mm, difference 0.05 mm)
- 27 mm and 1-1/16 inch (26.9875 mm, difference 0.0125 mm)
Other pairs (e.g., 6 mm and 1/4 inch, 8 mm and 5/16 inch) have differences >0.05 mm and are typically included separately in combined sets
| Size | Type | Size (mm) | Notes on Approximate Matches |
|---|---|---|---|
| 6 mm | Metric | 6.00 | Close to 1/4 inch (0.35 mm difference) |
| 1/4 inch | SAE | 6.35 | Close to 6 mm (0.35 mm difference) |
| 7 mm | Metric | 7.00 | |
| 8 mm | Metric | 8.00 | Close to 5/16 inch (0.0625 mm difference) |
| 5/16 inch | SAE | 7.9375 | Close to 8 mm (0.0625 mm difference) |
| 11/32 inch | SAE | 8.73125 | |
| 9 mm | Metric | 9.00 | |
| 3/8 inch | SAE | 9.525 | Close to 10 mm (0.475 mm difference) |
| 10 mm | Metric | 10.00 | Close to 3/8 inch (0.475 mm difference) |
| 11 mm | Metric | 11.00 | Close to 7/16 inch (0.1125 mm difference) |
| 7/16 inch | SAE | 11.1125 | Close to 11 mm (0.1125 mm difference) |
| 12 mm | Metric | 12.00 | |
| 1/2 inch | SAE | 12.7 | Close to 13 mm (0.3 mm difference) |
| 13 mm | Metric | 13.00 | Close to 1/2 inch (0.3 mm difference) |
| 14 mm | Metric | 14.00 | |
| 9/16 inch | SAE | 14.2875 | |
| 15 mm | Metric | 15.00 | |
| 5/8 inch | SAE | 15.875 | Close to 16 mm (0.125 mm difference) |
| 16 mm | Metric | 16.00 | Close to 5/8 inch (0.125 mm difference) |
| 17 mm | Metric | 17.00 | |
| 11/16 inch | SAE | 17.4625 | |
| 18 mm | Metric | 18.00 | |
| 19 mm | Metric | 19.00 | Approximately the same as 3/4 inch (0.05 mm difference) |
| 3/4 inch | SAE | 19.05 | Approximately the same as 19 mm (0.05 mm difference) |
| 20 mm | Metric | 20.00 | |
| 21 mm | Metric | 21.00 | Close to 13/16 inch (0.3625 mm difference) |
| 13/16 inch | SAE | 20.6375 | Close to 21 mm (0.3625 mm difference) |
| 22 mm | Metric | 22.00 | Close to 7/8 inch (0.225 mm difference) |
| 7/8 inch | SAE | 22.225 | Close to 22 mm (0.225 mm difference) |
| 15/16 inch | SAE | 23.8125 | Close to 24 mm (0.1875 mm difference) |
| 24 mm | Metric | 24.00 | Close to 15/16 inch (0.1875 mm difference) |
| 1 inch | SAE | 25.4 | |
| 1-1/16 inch | SAE | 26.9875 | Approximately the same as 27 mm (0.0125 mm difference) |
| 27 mm | Metric | 27.00 | Approximately the same as 1-1/16 inch (0.0125 mm difference) |
| 1-1/8 inch | SAE | 28.575 | |
| 30 mm | Metric | 30.00 | |
| 1-1/4 inch | SAE | 31.75 | Close to 32 mm (0.25 mm difference) |
| 32 mm | Metric | 32.00 | Close to 1-1/4 inch (0.25 mm difference) |
In combined wrench sets, only one wrench is typically provided for: 19 mm / 3/4 inch (19 mm and 19.05 mm) and 27 mm / 1-1/16 inch (27 mm and 26.9875 mm) because the difference is less than 0.05 mm. Other pairs like 6 mm / 1/4 inch, 8 mm / 5/16 inch, 10 mm / 3/8 inch, 11 mm / 7/16 inch, 13 mm / 1/2 inch, 16 mm / 5/8 inch, 21 mm / 13/16 inch, 22 mm / 7/8 inch, 24 mm / 15/16 inch, and 32 mm / 1-1/4 inch are close but typically included separately in combined sets due to differences >0.05 mm. These may be used interchangeably in non-precision applications.