Enter the design load limit (N) and the safety factor into the Working Load Limit Calculator. The calculator will evaluate the Working Load Limit. 

Safe Working Load Calculator

Use the main formula people usually want: Safe Working Load (SWL / WLL) = Minimum Breaking Strength ÷ Safety Factor. The second tab handles sling angle and hitch adjustments.

SWL / WLL Formula
Sling Angle / Capacity
Enter the minimum breaking strength or minimum breaking load for the component or sling.
Enter the allowable working load if you want to solve for breaking strength or safety factor.
Common examples are 4, 5, or 10 depending on the application.
Quick presets
Chain Sling 4
Wire Rope / Web Sling 5
General 6
General 8
Personnel 10
Leave this blank if you want to solve for allowable load from WLL per leg.
Leave this blank if you want to solve for required WLL per leg from the total load.
Number of legs
1 leg
2 legs
3 legs
4 legs
Used with the sling angle to estimate load share per leg.
Hitch type
Vertical
Choker
Basket
Basket uses a 2.0 factor. Choker uses a 0.8 factor in this estimate.
Lower angles sharply increase tension. Always verify with manufacturer load charts before lifting.
Results
Use this as a planning and estimation tool only. Actual allowable load depends on the exact sling, hardware, configuration, condition, and manufacturer rating.

Working Load Limit Formula

The following two example problems outline the steps and information needed to calculate the Working Load Limit.

WLL = DLL / SF

Variables:

  • WLL is the Working Load Limit (N)
  • DLL is the design load limit (N) 
  • SF is the safety factor 

To calculate the working load limit, divide the design load limit by the safety factor.

How to Calculate Working Load Limit?

The following steps outline how to calculate the Working Load Limit.

  1. First, determine the design load limit (N). 
  2. Next, determine the safety factor. 
  3. Next, gather the formula from above = WLL = DLL / SF.
  4. Finally, calculate the Working Load Limit.
  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.

design load limit (N) = 5,000

safety factor = 2.5

WLL = DLL / SF = ?