Towing Capacity Calculator
Estimate the maximum trailer weight you can safely tow from your GCWR, curb weight and payload.
How it works
Max trailer weight = GCWR − curb weight − (passengers + cargo)
Real-world towing capacity is limited by the gross combined weight rating (GCWR): the most the truck and its loaded trailer are allowed to weigh together. Start from the GCWR, subtract the truck’s own curb weight, then subtract everyone and everything riding inside it — the leftover is what the trailer can weigh, fully loaded. That is usually lower than the headline "max towing" number on the brochure, which assumes a nearly empty truck with just a driver. Tongue weight, the download the trailer places on the hitch, should sit near 10–15% of the trailer’s weight to keep it from swaying.
Worked example
A truck with a 14,000 lb GCWR and a 6,000 lb curb weight, loaded with 1,000 lb of passengers and cargo, can tow 14,000 − 6,000 − 1,000 = 7,000 lb. For a stable ride, the trailer’s tongue weight should be about 700–1,050 lb (10–15% of 7,000 lb).
Frequently asked questions
Why is this less than the brochure towing number?
Advertised max towing usually assumes a bare truck with only a 150 lb driver. Every passenger, tool box and cooler you add counts against the GCWR, cutting into what the trailer can weigh. This calculation reflects how the truck is actually loaded.
What is tongue weight and why does it matter?
Tongue weight is the downward force the trailer coupler puts on the hitch. Too little makes the trailer sway dangerously; too much overloads the rear axle. Keeping it near 10–15% of the loaded trailer weight gives stable, predictable towing.
Where do I find my GCWR and curb weight?
The GCWR is in the owner’s manual and often on the driver’s door jamb sticker. Curb weight is listed in the manual or specs; for the most accurate figure, weigh the truck at a public scale with a full tank and no cargo.
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Educational estimate. Real-world results vary with conditions, tuning and measurement.