Rating-based tow and payload check
Towing Capacity Calculator
Estimate the maximum loaded trailer weight allowed by your vehicle, combination and hitch ratings. Then check a planned trailer against GVWR, GCWR, payload, tongue-weight and hitch limits.
Towing-capacity formulas
base vehicle weight = curb weight + people, cargo and accessories
payload available for tongue weight = GVWR − base vehicle weight
trailer limit from vehicle payload = available payload ÷ tongue-weight fraction
trailer limit from hitch tongue rating = hitch tongue rating ÷ tongue-weight fraction
trailer limit from GCWR = GCWR − base vehicle weight
estimated maximum loaded trailer = smallest of the manufacturer tow rating, hitch trailer rating, vehicle-payload limit, hitch-tongue limit and GCWR limit
For a planned trailer, the tool calculates tongue weight = loaded trailer weight × tongue-weight fraction, adds that tongue weight to the tow vehicle for the GVWR check, and adds the full trailer weight to the base vehicle for the GCWR check.
Checked example
| Input | Value |
|---|---|
| Vehicle ratings and weight | 7,000 lb GVWR; 5,000 lb curb; 13,000 lb GCWR |
| Tow and hitch ratings | 7,500 lb manufacturer trailer rating; 8,000 lb hitch trailer rating; 900 lb hitch tongue rating |
| Trip load | 600 lb people/cargo; 12% estimated tongue weight; 6,000 lb planned loaded trailer |
The base vehicle weighs 5,600 lb, leaving 1,400 lb before tongue weight. The GCWR permits 7,400 lb of loaded trailer, which is lower than the 7,500 lb manufacturer rating, the 8,000 lb hitch rating, the 11,666.7 lb payload-derived limit and the 7,500 lb hitch-tongue-derived limit. The calculator therefore estimates a 7,400 lb maximum loaded trailer, with GCWR as the binding limit.
A 6,000 lb loaded trailer at 12% puts an estimated 720 lb on the tongue. The loaded tow vehicle is 6,320 lb and the combination is 11,600 lb, leaving 680 lb below GVWR and 1,400 lb below GCWR.
Limits and safe use
- Do not substitute trailer GVWR for actual loaded trailer weight. Include water, fuel, batteries, propane, equipment and cargo.
- Tongue or pin weight consumes tow-vehicle payload. The correct percentage depends on trailer type and manufacturer instructions; 12% is only the editable example.
- This tool does not check front or rear GAWR, tire and wheel ratings, brake requirements, hitch configuration, weight-distribution limits, sway control, local laws or dynamic stability.
- Factory tow ratings can depend on engine, axle ratio, drivetrain, cab, wheelbase, cooling package and other equipment. Use the rating for the exact vehicle configuration.
- No blanket “80% rule” replaces the published ratings. Keep suitable real-world margin for measurement uncertainty, terrain, weather and operating conditions.
Definitions and rating locations: Ford towing terms and guides and the Towing a Trailer safety guide republished by Oregon DOT.