How to Use the Caster Load Rating Calculator
When sizing casters for a cart or mobile rack, simply dividing total load by the number of casters can lead you to pick an undersized caster. On a floor that isn't perfectly flat, one caster commonly lifts slightly off the ground, so caster manufacturers widely recommend dividing by the number of casters minus one instead.
This calculator divides the total load (cargo plus cart weight) by "caster count minus one," then multiplies by your chosen safety factor to find the minimum load rating actually needed per caster. Choose a safety factor between 1.25 and 2.0 depending on use conditions - more frequent movement and higher impact potential call for a higher factor.
Select a caster with a published load rating (from the manufacturer's catalog) equal to or greater than the calculated value. If the floor is especially uneven or you're moving high-value precision equipment, add extra margin beyond the calculated result.
Frequently Asked Questions
On a floor that isn't perfectly flat, one caster can lift slightly off the ground, leaving the remaining casters to carry the load. Sizing by count minus one is a common practice recommended by caster manufacturers.
Use 1.25 for mostly stationary use, 1.5 or higher for frequent movement or expected impact, and up to 2.0 when moving precision equipment or high-value materials.