Thread Pitch Calculator
Calculate the pitch of your threaded fastener very easily with this thread pitch calculator.
Pitch1.27 mm0.05 in — the distance between adjacent threads
Threads per inch20
Pitch in inches0.05 in
Lead1.27 mmsingle start, so lead = pitch
Threads per cm7.874
Threads over 1 in20
Turns to advance that far20
Advance per full turn1.27 mm0.05 in
Advance per quarter turn0.3175 mm
Nearest standard metric pitch1.25 mmdiffers by 0.02 mm
Nearest common imperial thread1/4-2020 TPI
The formula
pitch = 1 ÷ TPI; TPI = 1 ÷ pitch
Pitch and lead are different
Pitch is the distance from one thread to the next. Lead is how far the nut advances in one full turn. On an ordinary single-start thread they are the same number, which is why the terms get used interchangeably — but on a two-start thread the lead is twice the pitch, and the nut travels twice as fast for the same thread form.
Metric threads are specified by pitch and imperial ones by threads per inch, which are reciprocals. Note that a coarse metric pitch is a large number while a coarse imperial thread is a small TPI — a reliable source of confusion.