How is towing capacity calculated?

The manufacturer sets a maximum trailer weight per configuration, normally GCWR minus base curb weight, validated to SAE J2807. This calculator does not compute a rating; it checks your loaded trailer, tongue weight, passengers and cargo against the manufacturer's four published limits: max trailer, max tongue, payload (GVWR − curb) and GCWR.

What tongue weight should I use?

10–15% of the loaded trailer weight for a conventional trailer; 13% is the default here. Tongue weight counts against the tow vehicle's payload.

Which limit usually binds first?

Payload. A 10,000 lb trailer at 13% tongue weight uses 1,300 lb of payload before passengers and cargo, which exceeds many half-ton trucks' remaining payload.

Towing calculator

Checks your loaded trailer against the four manufacturer limits (max trailer, max tongue, payload, GCWR) and shows which one binds first. Vehicles in the list carry their published figures; otherwise enter yours from the door-jamb label and owner's manual.

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Vehicle

Max trailer weight (lb)*Max tongue weight (lb)GVWR (lb)GCWR (lb)Curb weight (lb)

Passengers (lb)Cargo in vehicle (lb)Loaded trailer weight (lb)*

Tongue weight

% of trailer% measured (lb)

Enter at least a max trailer rating and a trailer weight.

Safety: Manufacturer ratings assume a properly equipped vehicle. Your vehicle's certification label (driver's door jamb) and owner's manual override this site.

Method

Tongue weight = trailer × percentage (default 13%), or your measured value. Remaining payload = payload − passengers − cargo − tongue weight, where payload is the published figure or GVWR − curb weight. Combined weight = curb + passengers + cargo + loaded trailer, compared with GCWR. Each limit passes when the value is less than or equal to the limit; the binding constraint is the failing limit with the largest overage, or the passing limit with the smallest margin.

Recommendations: hitch class from the vehicle's max trailer rating (classes); brake controller when the trailer exceeds 1,500 lb (state rules vary); weight-distribution hitch above the manufacturer's threshold for the row or above 50% of curb weight (guide).

Frequently asked

How is towing capacity calculated?: The manufacturer sets a maximum trailer weight per configuration, normally GCWR minus base curb weight, validated to SAE J2807. This calculator does not compute a rating; it checks your loaded trailer, tongue weight, passengers and cargo against the manufacturer's four published limits: max trailer, max tongue, payload (GVWR − curb) and GCWR.
What tongue weight should I use?: 10–15% of the loaded trailer weight for a conventional trailer; 13% is the default here. Tongue weight counts against the tow vehicle's payload.
Which limit usually binds first?: Payload. A 10,000 lb trailer at 13% tongue weight uses 1,300 lb of payload before passengers and cargo, which exceeds many half-ton trucks' remaining payload.

Terms: GCWR · GVWR · payload · tongue weight. Need the range of tongue weights for a trailer? Tongue weight calculator.