Pitch conversion Threads per inch (TPI) to Metric and vice versa

 

 

    TPI      Metric pitch in mm                     Metric pitch in mm      TPI      
13 1.9   0.25 101  
14 1.8   0.3 84  
16 1.5   0.35 72.5  
18 1.4   0.4 63.5  
20 1.2   0.45 56.4  
24 1.0   0.5 50.8  
27 0.94   0.6 42.3  
28 0.90   0.7 36.2  
32 0.79   0.75 33.8  
36 0.70   0.8 31.7  
      1.0 25.4  
      1.25 20.3  
      1.5 16.9  
      1.75 14.5  
      2.0 12.7  
      2.5 10.1  
      3.0 8.4  
      3.5 7.2  
      4.0 6.3  
      4.5 5.6  
      5.0 5  
      5.5 4.6  
      6.0 4.2  
           
        e&o.e.  

 

 

Metric Thread gauge