Enter the number of threads per inch and the rotational speed into the calculator to determine the tapping speed. This calculator can also evaluate any of the variables given the others are known.

Tapping Speed Formula

The following formula is used to calculate the tapping speed.

TS = (N * RPM) / 1000


  • TS is the tapping speed (meters per minute) N is the number of threads per inch RPM is the rotational speed (revolutions per minute)

To calculate the tapping speed, multiply the number of threads per inch by the rotational speed. Then divide the result by 1000.

What is a Tapping Speed?

Tapping speed refers to the rate at which a tap or die cuts threads into a material in machining processes. It is usually measured in revolutions per minute (RPM). The appropriate tapping speed depends on several factors including the type of material being tapped, the tap size, and the type of tap being used. Using the correct tapping speed is crucial to prevent damage to the tap or the material and to ensure the accuracy and quality of the threading.

How to Calculate Tapping Speed?

The following steps outline how to calculate the Tapping Speed.

  1. First, determine the number of threads per inch (N).
  2. Next, determine the rotational speed (RPM).
  3. Next, gather the formula from above = TS = (N * RPM) / 1000.
  4. Finally, calculate the Tapping Speed.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

number of threads per inch (N) = 8

rotational speed (RPM) = 1200