Enter the speed of two objects into the calculator to determine the closing speed.

Closing Speed Calculator

Enter any 2 values to calculate the missing variable

Closing Speed Formula

The following formula is used to calculate the closing speed between two objects.

CS = S1 + S2

Variables:

  • CS is the closing speed
  • S1 is the speed of object 1
  • S2 is the speed of object 2

To calculate the closing speed, simply add the speeds of the two objects.

What is Closing Speed?

Closing speed is the rate at which the distance between two moving objects decreases. It is a crucial concept in various fields such as aviation, automotive safety, and collision avoidance systems. Understanding closing speed helps in predicting potential collisions and taking necessary actions to avoid them. The closing speed is essentially the sum of the speeds of the two objects moving towards each other.

How to Calculate Closing Speed?

The following steps outline how to calculate the Closing Speed.


  1. First, determine the speed of object 1 (S1).
  2. Next, determine the speed of object 2 (S2).
  3. Finally, calculate the closing speed using the formula CS = S1 + S2.
  4. After inserting the values 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.

Speed of Object 1 (S1) = 30 units/time

Speed of Object 2 (S2) = 20 units/time