Enter the weight per unit length (lb/in), the length of the span (in), and the total tension (lb) into the Chain Sag Calculator. The calculator will evaluate the Chain Sag.

## Chain Sag Formula

The following formula is used to calculate the Chain Sag.

S = w*l^2 / (8*T)

Variables:

- S is the Chain Sag (in)
- w is the weight per unit length (lb/in)
- l is the length of the span (in)
- T is the total tension (lb)

To calculate the chain sag, square the length of the span, multiply by the weight per unit length, then divide by the product of 8 times the total tension.

## How to Calculate Chain Sag?

The following steps outline how to calculate the Chain Sag.

- First, determine the weight per unit length (lb/in).
- Next, determine the length of the span (in).
- Next, determine the total tension (lb).
- Next, gather the formula from above = S = w*l^2 / (8*T).
- Finally, calculate the Chain Sag.
- 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.

weight per unit length (lb/in) = 40

length of the span (in) = 5

total tension (lb) = 30

S = w*l^2 / (8*T) =** ** ?