Trailer towing calculator
Enter your truck's door-sticker numbers and your real, loaded trailer weight. Get the lowest limiting number, the safe tongue-weight band, payload margin, and a brake controller starting gain — with a loud warning the moment any rating is exceeded.
Four limits decide whether you can tow it. This tool computes each margin and tells you which one is binding — and screams if any is negative.
Over payload? A weight-distribution hitch won't fix that — you need a lighter trailer. Hitches and WDHs on Amazon: Class III/IV receivers, weight-distribution kits with sway control.
Tongue weight must be 10–15% of the fully loaded trailer. Enter trailer weight, then either a measured tongue weight or a bathroom-scale reading taken with the lever-arm method.
The limit that actually bites. Tongue weight counts against payload — so do passengers, the fifth-wheel hitch pin weight, bed gear, and the toolbox you forgot.
A starting gain for your electric brake controller — then calibrate it with the manual-slider test, every time the load changes.
Why the "lowest number" rule matters
A truck is a system of ratings, and towing capacity marketing quotes only the biggest one. The tow rating is what the drivetrain can pull. The GCWR caps truck + trailer together. The payload rating caps everything sitting on the truck — including the trailer's tongue weight. The hitch class caps what the receiver itself can hold. Your real capacity is the smallest of the four after the load is actually applied. Half-ton trucks towing big campers almost always hit the payload limit first, at tongue weights of 800–1,000 lb — long before the tow rating is close.
Typical numbers reference
| Rig | Payload rating | Tow rating (WDH) | Realistic max camper |
|---|---|---|---|
| Half-ton crew cab (F-150 / Silverado 1500 class) | 1,550–1,850 lb | 11,000–13,000 lb | ~6,500–7,500 lb |
| 3/4-ton (F-250 / 2500 class) | 2,800–3,300 lb | 15,000–18,000 lb | ~10,000–12,000 lb |
| 1-ton (F-350 / 3500 class) | 3,800–4,500 lb | 20,000+ lb | ~14,000+ lb |
Realistic max assumes ~13% tongue weight, 500 lb of passengers, 200 lb of gear, and the truck's own hardware. Always verify against the door-jamb sticker of the specific truck, not the brochure maximum.
Guides
Towing capacity explained: tow rating vs GCWR vs payload
The four ratings, how they interact, and why the truck with "13,000 lb towing" on the billboard stops at 7,000 in the real world.
Tongue weight: the 10–15% rule and how to actually measure it
Sway physics, the bathroom-scale lever method, and where to shift your cargo.
Best hitches and weight-distribution setups
Class III vs IV vs V, WDH with sway control, and matching hardware to your numbers — ranked by the math above.
GeneratorSizer ↗ · SolarSizer ↗ · WeldingCalc ↗ · Battery Bank Sizer ↗
Sister calculators: size the generator, solar, welder, and battery bank that ride along on your trips.