How to calculate Percentage of Crane SWL

How to calculate Percentage of Crane SWL

Learn calculation of Crane SWL Percentage, you can calculate easily by a frequency used formula [(weight of load + Total weight of Lifting accessories) × 100/SWL@max radius], let's elaborate with an example.

How to calculate "Percentage of Crane SWL"

What does percentage of crane SWL mean?

The “Percentage of Crane SWL” is a measure of how much the crane’s Safe Working Load (SWL) is being utilized in lifting operations; it shows how far the lifted object has come to reaching maximum safe capacity of the crane. For instance, should a 10 ton crane be used to lift a five-ton load, then the percentage of crane SWL would be 50%. This information is important for ensuring that lifting operations are safe and efficient since exceeding the percentage of SWL can cause accidents or result in structural failure.

What is crane SWL?

SWL stands for Safe Working Load. It stands for the heaviest weight that a normal working condition can safely handle on machines like cranes or lifts. The limit results from considerations such as the design, robustness, and capabilities while in operation. If you exceed such limits you will risk structural failures, accidents among other safety hazards. Therefore it’s necessary that operators adhere to manufacturer provided guidelines on SWL and also conduct frequent surveys to ascertain safety during lifting operations.

Formula for Crane SWL Percentage:

[(weight of load + Total weight of Lifting accessories)× 100/SWL@max radius]


  • Weight of load in ton (Load means material to be lifted).
  • Weight of lifting accessories in ton (Hook block weight including rigging wire rope).
  • SWL on maximum radius (Crane maximum safe working load)

Lets put some values in formula:

Suppose a crane of SWL (capacity) 100 ton with 0.5 ton of lifting accessories is going to lift 10 ton load, so here:-

  • Weight of load = 10 ton.
  • Weight of lifting accessories = 0.5 ton.
  • SWL at maximum radius = 100 ton.

While putting values in crane SWL percentage formula:-

[(weight of load + Total weight of Lifting accessories) × 100/SWL@max radius]

How to calculate "Percentage of Crane SWL" formula

[(10 + 0.5) × 100/100]

(10.5) × 1


So here crane SWL percentage is 10.5

Means in this scenario we are going to use 10.5% of total crane SWL.

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