About this trailer tire load calculator
Trailer tires must support the portion of trailer weight carried by the axles. This tool estimates average load per tire and compares it with the sidewall load rating you enter.
How the calculation works
- Enter loaded trailer weight and tongue-weight percentage.
- Enter the number of load-carrying trailer tires.
- Enter the maximum load shown on one tire at its specified cold pressure.
- Choose a planning reserve percentage to see both actual utilization and a more conservative target capacity.
Get a better result
- Use the exact sidewall rating for the tire and pressure you actually run.
- Tire age, condition, inflation, speed and heat matter in addition to rated capacity.
- Account for side-to-side imbalance instead of assuming perfect sharing.
Important: Tow Capacity Lab provides planning math, not a certification that a combination is safe, legal or manufacturer-approved. The lowest applicable rating always controls.
Frequently asked questions
What does load range C, D or E mean?
Load range relates to tire construction and pressure capability, but the actual pounds of capacity printed on the sidewall is the figure to compare with your load.
Why include reserve capacity?
A reserve target is a planning buffer. It does not replace the tire manufacturer's instructions or a proper loading and inflation strategy.
