Metric Thread Pitch Table – Sizes & Charts (Monster Bolts)
Metric fasteners differ drastically from their US counterparts and are absolutely not interchangeable. US screws use Threads Per Inch (TPI), while metric screws use Thread Pitch, which is the distance in millimeters between two thread peaks. The smaller the pitch number, the finer the thread.
For example, an M8 screw with a standard thread pitch has 1.25 mm between each thread peak. A helpful trick is to measure the distance across 10 threads, then move the decimal point one place to the left — this makes identifying the pitch easier and more accurate than trying to measure a single thread spacing.
Metric Thread Pitch Chart
| Screw Size | Standard / Coarse Pitch (mm) | Fine Pitch (mm) |
|---|---|---|
| M1.6 | 0.35 | – |
| M2 | 0.40 | – |
| M2.5 | 0.45 | – |
| M3 | 0.50 | – |
| M3.5 | 0.60 | – |
| M4 | 0.70 | – |
| M5 | 0.80 | – |
| M6 | 1.00 | – |
| M8 | 1.25 | 1.00 |
| M10 | 1.50 | 1.25 |
| M12 | 1.75 | 1.50 |
| M14 | 2.00 | 1.50 |
| M16 | 2.00 | – |
| M18 | 2.50 | – |
| M20 | 2.50 | – |
Frequently Asked Questions
What is metric thread pitch?
Metric thread pitch is the distance between two thread peaks, measured in millimeters. For example, an M8×1.25 screw has 1.25 mm between each thread.
Can I use metric screws with US fasteners?
No. Metric and US (SAE) fasteners are not interchangeable. Even if sizes seem close, the threads differ and can damage components or create unsafe joints.
How do I measure thread pitch accurately?
The easiest method is to measure across 10 threads with calipers, then move the decimal point one place to the left. This is more accurate than trying to measure a single thread.
What’s the difference between coarse and fine thread?
Coarse thread screws have larger spacing between threads and are more common for general use. Fine thread screws have smaller spacing, allowing for better tension control and resistance to vibration.