How to Use the Chain Hoist Capacity Calculator
Sizing a chain hoist right at the bare load weight leaves no margin for rigging hardware or center-of-gravity offset, which can push the actual load past the hoist's rated capacity. This calculator adds a safety margin (10-25%) to the load weight, then recommends the smallest standard commercial capacity (0.25, 0.5, 1, 2, 3, 5, 10, or 20 tons) that meets the resulting requirement.
The safety margin accounts for the weight of shackles, slings, and hooks, plus center-of-gravity offset and general working margin. For precision lifts or high-value equipment, applying a margin of 25% or more is the safer choice.
In the US, overhead chain hoists are governed by ASME B30.16 (Overhead Hoists), which sets design, marking, and inspection requirements. Meeting the capacity requirement alone doesn't make a hoist safe to use - always verify its inspection history and load rating markings before operating it.
Frequently Asked Questions
Beyond the load's own weight, rigging hardware (shackles, slings, hooks), center-of-gravity offset, and margin against the rated capacity all add up, so it's safer to size with extra headroom above the bare required capacity.
Capacity alone is not enough - also check the hoist's own design factor (load chain is typically required to have a minimum design factor of 4:1 against breaking strength) and its inspection and load rating markings. In the US, overhead hoists fall under periodic inspection requirements.