Towing Payload Calculator

About this calculator

A tow vehicle’s available payload is what’s left of its Gross Vehicle Weight Rating (GVWR) after subtracting both its own curb weight and the trailer’s tongue weight — the downward force the trailer’s hitch puts on the tow vehicle, which for a conventional (non-weight-distributing) hitch is typically 10–15% of the loaded trailer’s total weight: Available payload = GVWR − Curb weight − Tongue weight.

Tongue weight counts against the tow vehicle’s payload capacity just like passengers or cargo in the bed or cabin do, which is why a vehicle can be well within its towing capacity rating and still be overloaded on payload once the trailer, passengers, and gear are all accounted for. Truck and SUV owners use this calculation before a trip to confirm they’re not exceeding GVWR or rear axle rating, since doing so affects braking, handling and is often a safety-inspection and liability issue. This calculator takes your GVWR, curb weight, trailer weight and tongue-weight percentage and returns the payload still available.