Towing Capacity Calculator

This works out what is left to tow from ratings you read off your own vehicle rather than rating anything itself. Enter the GCWR, the GVWR, the curb weight and what you are carrying and it returns the trailer weight allowed by the GCWR, the trailer weight allowed by what is left of the payload, and which of the two limits bites first. A second mode checks measured tongue weight as a share of the loaded trailer, and a third runs the door placard payload against people, cargo, accessories and pin weight. Tongue weight comes out of the payload, which is the part most people leave out. The door jamb placard and the owner's manual are the only authority for any of these numbers, and exceeding a rating is a braking and control problem before it is a legal one.

Calculator Type
Weights In
Every box on this form and every answer below follows this choice. Enter the ratings in whichever unit your own placard and manual print them in. The percentages come out the same either way.
Vehicle and trailer together. Usually in the towing section of the owner's manual.
The vehicle on its own, from the door jamb placard.
As it sits empty, with fuel. A scale ticket beats the brochure.
Bed load, roof rack, toolbox, hitch hardware, anything bolted on after the factory.
Conventional trailers are commonly 10 to 15 percent, fifth wheels and goosenecks 15 to 25.
Leave at zero if the manual does not give one. Entering it lets the tool tell you which limit bites first.
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Weights In
Every box on this form and every answer below follows this choice. Enter the ratings in whichever unit your own placard and manual print them in. The percentages come out the same either way.
Everything in and on the trailer, from a scale if you can.
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Weights In
Every box on this form and every answer below follows this choice. Enter the ratings in whichever unit your own placard and manual print them in. The percentages come out the same either way.
The sticker reads "the combined weight of occupants and cargo should never exceed".
Bed liner, roof rack, tool box, bull bar, the hitch itself.
Leave at zero if nothing is hitched up. A zero means the same thing in either unit.
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