Enter the synchronous speed (RPM) and the rotational speed (RPM) into the Slip Rate Calculator. The calculator will evaluate the Slip Rate. 

Slip Rate Formula

The following two example problems outline the steps and information needed to calculate the Slip Rate.

SR = (Ns – N) / Ns*100


  • SR is the Slip Rate (%)
  • Ns is the synchronous speed (RPM) 
  • N is the rotational speed (RPM) 

How to Calculate Slip Rate?

The following steps outline how to calculate the Slip Rate.

  1. First, determine the synchronous speed (RPM). 
  2. Next, determine the rotational speed (RPM). 
  3. Next, gather the formula from above = SR = (Ns – N) / Ns*100.
  4. Finally, calculate the Slip Rate.
  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.

synchronous speed (RPM) = 500

rotational speed (RPM) = 400

SR = (Ns – N) / Ns*100 = ?