M12 vs 1/2-13 UNC Screw Size Comparison
Overview
Dimensional reference for M12 metric and 1/2-13 UNC imperial fasteners. While close in size, these threads are not compatible.
Comparison Table
| Standard | Size | Diameter (mm) | Pitch / TPI | Tap Drill |
|---|---|---|---|---|
| Metric | M12 | 12.00 mm | 1.75 mm | 10.2 mm |
| Imperial | 1/2”-13 UNC | 12.70 mm | 13 TPI | 10.8 mm (27/64”) |
FAQ
Is M12 the same as 1/2 inch?
No. A 1/2 inch bolt (12.70 mm) is larger than an M12 bolt (12.00 mm). Attempting to use an M12 bolt in a 1/2” hole will result in significant play and potential failure.
Source Standard
ISO 261 / ASME B1.1