Thread Pitch Conversion

Approximate Pitch/TPI - Metric to Inch Conversion Chart
Pitch (mm) Calculated Pitch (inches) Threads per inch Pitch (inches) Calculated Inch Pitch (mm)
0.20 0.007874 80 0.012500 0.32
0.25 0.009843 72 0.013899 0.35
0.30 0.011811 64 0.015625 0.40
0.35 0.013780 56 0.017857 0.45
0.40 0.015748 48 0.020833 0.53
0.45 0.017717 44 0.022727 0.58
0.50 0.019685 40 0.025000 0.64
0.55 0.021654 36 0.027778 0.71
0.60 0.023622 32 0.031250 0.79
0.65 0.025591 28 0.035714 0.91
0.70 0.027559 27 0.037037 0.94
0.75 0.029528 24 0.041667 1.06
0.80 0.031496 20 0.050000 1.27
1.00 0.039370 18 0.055556 1.41
1.25 0.049213 16 0.062500 1.59
1.50 0.059055 14 0.071429 1.81
1.75 0.068898 13 0.076923 1.95
2.00 0.078740 12 0.083333 2.12
2.50 0.098425 11.5 0.086957 2.21
3.00 0.118110 11 0.090909 2.31
3.50 0.137795 10 0.100000 2.54
4.00 0.157480 9 0.111111 2.82
4.50 0.177165 8 0.125000 3.18
5.00 0.196850 7 0.142857 3.63
5.50 0.216535 6 0.166667 4.23
6.00 0.236220 5 0.200000 5.08
8.00 0.314960 4.5 0.222222 5.64
    4 0.250000 6.35