🔍 Thread Identification Tool
Identify thread pitch and type by measuring your fastener
Unified (Inch) Thread Identification
How to Measure TPI:
Use a thread pitch gauge or count the number of thread peaks in exactly 1 inch. For small screws, count threads in 1/2 inch and multiply by 2.
Metric (ISO) Thread Identification
How to Measure Pitch:
Use a thread pitch gauge or measure the distance from one thread peak to the next in millimeters. Common pitches: 0.5mm, 0.75mm, 1.0mm, 1.25mm, 1.5mm, 2.0mm.
Thread Identification Results
Quick Reference: Common Thread Sizes
| Size | Coarse (UNC) | Fine (UNF) | Tap Drill |
|---|---|---|---|
| #4 | 40 TPI | 48 TPI | 3/32" |
| #6 | 32 TPI | 40 TPI | 7/64" |
| #8 | 32 TPI | 36 TPI | 9/64" |
| #10 | 24 TPI | 32 TPI | 5/32" |
| 1/4" | 20 TPI | 28 TPI | #7 (0.201") |
| 5/16" | 18 TPI | 24 TPI | F (0.257") |
| 3/8" | 16 TPI | 24 TPI | 5/16" |
| 1/2" | 13 TPI | 20 TPI | 27/64" |
Metric Thread Reference
| Size | Coarse Pitch | Fine Pitch | Tap Drill |
|---|---|---|---|
| M3 | 0.5mm | - | 2.5mm |
| M4 | 0.7mm | 0.5mm | 3.3mm |
| M5 | 0.8mm | 0.5mm | 4.2mm |
| M6 | 1.0mm | 0.75mm | 5.0mm |
| M8 | 1.25mm | 1.0mm | 6.8mm |
| M10 | 1.5mm | 1.25mm | 8.5mm |
| M12 | 1.75mm | 1.25mm | 10.2mm |