Thread Pitch Calculator – Thread Pitch Diameter Calculator 2025
To calculate thread pitch, divide 1 by the number of threads per inch (TPI) or threads per millimeter for metric threads.
The Thread Pitch Calculator is a practical tool for machinists, engineers, and DIY enthusiasts involved in threading and fastener design. Thread pitch indicates the spacing between threads, playing a crucial role in determining the fit, function, and strength of screws, bolts, and nuts.
Formula
P = 1 / n
| Variable | Description | 
|---|---|
| P | Thread Pitch (in inches or millimeters) | 
| n | Number of threads per inch (TPI) or mm | 
Solved Calculations
Example 1: Thread Pitch for a Standard 8 TPI Thread
| Step | Value | 
|---|---|
| Number of Threads per Inch (n) | 8 | 
| Thread Pitch (P) | 1 ÷ 8 = 0.125 inches | 
Example 2: Thread Pitch for a Metric M10 × 1.5 Bolt
| Step | Value | 
|---|---|
| Number of Threads per Millimeter (n) | 1.5 | 
| Thread Pitch (P) | 1 ÷ 1.5 = 0.666 mm | 
 
  
  
  
  
 