How the Caster Load Formula Works
The calculator applies the standard load formula used across this site and in our caster buying guide:
Rated capacity = (Empty weight + Max load) × Safety factor ÷ Number of casters
- Add empty weight and maximum load — the full weight the casters ever carry.
- Apply the dynamic safety factor — 1.25 standard, 1.5 towed, 2.0 shock. This accounts for lateral and impact forces a static number misses.
- Divide by the number of casters — the per-caster rating you must meet or exceed.
Common Mistakes in Caster Load Calculations
- Forgetting the equipment\'s own weight — people size for the payload and ignore the cart, which can be a third of the total.
- Ignoring dynamic load — a caster rated exactly at the static number fails early once it crosses a threshold or is towed. The safety factor exists for this.
- Assuming even distribution — four casters rarely share load equally; design uneven or safety-critical loads to one fewer contact point.
Load Ratings by Application
Once you have a per-caster rating, match it to the right specification for your environment:
- Hospital beds & medical carts — see hospital bed casters and medical cart wheels.
- Warehouse & heavy industrial — see warehouse casters and heavy-duty casters.
- Tread material for your rating & floor — see the caster materials guide.
Need help specifying casters for your application? Get matched with a supplier free.