Enter the line weight (N), the line length (m), and the line sag (m) into the Slackline Tension Calculator. The calculator will evaluate the Slackline Tension. 

Slackline Tension Formula

The following formula is used to calculate the Slackline Tension. 

ST  =  (LW*L) / (4*S)


  • ST is the Slackline Tension (N)
  • LW is the line weight (N) 
  • L is the line length (m) 
  • S is the line sag (m) 

How to Calculate Slackline Tension?

The following steps outline how to calculate the Slackline Tension.

  1. First, determine the line weight (N).
  2. Next, determine the line length (m). 
  3. Next, determine the line sag (m). 
  4. Next, gather the formula from above = ST  =  (LW*L) / (4*S).
  5. Finally, calculate the Slackline Tension.
  6. 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.

line weight (N) = 45

line length (m) = 30

line sag (m) = 5

ST  =  (LW*L) / (4*S) =  ?