Thread conversion table
Due to the differences in thread angles and pitches, the thread sizes shown below are not directly interchangeable with each other. This table is only to help find a nearest equivalent sized fastener.
| Metric coarse | Metric fine | BSF/BSW | UNC | UNF |
|---|---|---|---|---|
| M2 x 0.4 | - | - | 1-64 | 1-72 |
| M2.5 x 0.45 | - | - | 3-48 | 3-56 |
| M3 x 0.5 | - | - | 4-40 | 4-48 |
| M3.5 x 0.6 | - | - | 6-32 | 6-40 |
| M4 x 0.7 | - | - | 8-32 | 8-36 |
| M5 x 0.8 | - | - | 10-24 | 10-32 |
| M6 x 1 | M6 x 0.75 | 1/4" | 1/4-20 | 1/4-28 |
| M8 x 1.25 | M8 x 1 | 5/16" | 5/16-18 | 5/16-24 |
| M10 x 1.5 | M10 x 1.25 | 3/8" | 3/8-16 | 3/8-24 |
| M12 x 1.75 | M12 x 1.25 | 1/2" | 1/2-13 | 1/2-20 |
| M14 x 2 | M14 x 1.5 | 9/16" | 9/16-12 | 9/16-18 |
| M16 x 2 | M16 x 1.5 | 5/8" | 5/8-11 | 5/8-18 |
| M20 x 2.5 | M20 x 1.5 | 3/4" | 3/4-10 | 3/4-16 |
| M24 x 3 | M24 x 2 | 1" | 1-8 | 1-12 |
| M30 x 3.5 | M30 x 2 | 1-1/8" | 1 1/4-7 | 1 1/8-12 |
| M36 x 4 | M36 x 3 | 1-3/8" | 1 1/2-6 | 1 1/4-12 |