How to use this calculator
- Pull your ratings. GVWR from the door sticker; GCWR and the configuration tow rating from the owner's manual or tow guide.
- Weigh the truck. Curb weight from a scale ticket with full fuel beats the brochure; add the real people-and-gear weight that rides along.
- Enter the loaded trailer. Actual loaded weight — the trailer plus everything strapped to it — at your tongue percent (~12% to start).
- Read both verdicts. Max trailer answers "can it pull it"; payload-after-tongue answers "can it carry the hitch" — the second one fails first on most trucks.
- Confirm on a scale. A CAT scale ticket of the hitched rig (steer / drive / trailer axles) verifies GVWR, GAWRs and tongue weight in one pass.
How it works
Towing questions are weight-budget questions, and there are two budgets, not one. The combined budget (GCWR) limits what the drivetrain may move; the truck budget (GVWR) limits what the truck itself may weigh — and the trailer's tongue weight spends from the truck budget:
max trailer = GCWR − curb − occupants/cargo payload left = GVWR − curb − occupants/cargo − tongue
Marketing quotes the first number under ideal assumptions; driveways fill with overloaded half-tons because of the second. This calculator runs both from your sticker values — no vehicle database, because the only ratings that matter are the ones on your truck's door and in its tow guide — and caps the result with the published tow rating when you enter it.
The neighbors: the tongue weight calculator digs into load placement on the trailer itself, the payload calculator works the GVWR budget alone, and the axle load calculator covers the GAWR checks this page deliberately leaves to a scale.
Worked example
Verified against the live calculator
A typical half-ton: GVWR 7,000 lb, GCWR 16,000 lb,
curb 5,600 lb, with 500 lb of family and gear
aboard, hitching an 8,000 lb loaded camper at 12% tongue:
max trailer = 16,000 − 5,600 − 500 = 9,900 lb → 8,000 lb trailer passes with 1,900 lb to spare
payload = 7,000 − 5,600 − 500 = 900 lb; tongue = 8,000 × 12% = 960 lb → −60 lb
Same truck, same trailer: the towing check passes comfortably and the payload check fails before the trailer moves an inch. That asymmetry is the single most common towing mistake, and it is why this page badges payload after tongue right next to max trailer. The fixes are the usual ones — less bed cargo, a lighter trailer, moving load behind the trailer axle (carefully, sway), or the three-quarter-ton the salesman didn't mention.
Frequently asked questions
How do I calculate my real towing capacity?
From your own ratings: max trailer = GCWR − (curb weight + everyone and everything in the truck), then capped by the manufacturer's published tow rating for your configuration. The brochure's headline number assumes a stripped truck with one 150 lb driver — your real capacity is lower the moment people and gear get in.
Why does payload matter more than towing capacity?
Because tongue weight (10-15% of the trailer) counts against the truck's PAYLOAD, and payload runs out first on most half-tons. A truck rated to tow 9,900 lb with 900 lb of payload left cannot legally hitch an 8,000 lb trailer at 12% tongue — the 960 lb of tongue weight alone exceeds the remaining payload.
What should tongue weight be?
About 10-15% of loaded trailer weight for conventional (bumper-pull) trailers — under ~10% invites sway, over ~15% overloads the rear axle and lightens the steering. Fifth-wheel and gooseneck pin weights run ~15-25% and load the bed directly.
Where do I find GVWR, GCWR and curb weight?
GVWR (and GAWRs) are on the driver-door sticker. GCWR and the configuration-specific tow rating are in the owner's manual or the manufacturer's tow guide. Curb weight: weigh the actual truck at a CAT scale with full fuel — options and accessories make brochure curb weights optimistic.
Why is my published tow rating lower than GCWR minus curb weight?
The rating (SAE J2807 based since the mid-2010s) also covers axle capacity, cooling, frame, brakes and hitch structure under standardized grades and temperatures. When the published rating is lower than the arithmetic, the rating governs — enter it and this calculator caps the result.
Method & assumptions
- Weight arithmetic on user-entered ratings only — no vehicle spec database, by design. Door sticker, owner's manual and a scale ticket are the sources of truth.
- The published configuration tow rating (SAE J2807 based) governs when lower than the GCWR arithmetic; axle ratings (GAWR), hitch/receiver class and weight-distribution hitch requirements are separate hard limits not modeled.
- Tongue percent applies to the loaded trailer weight; conventional trailers ~10-15%, fifth-wheel/gooseneck pin weights ~15-25% (and load the bed inside GVWR the same way).
- Braking requirements (trailer brakes above jurisdictional thresholds), licensing classes and posted limits are regulatory questions outside this screen.