Key takeaways
- Payload = GVWR − curb weight — the total you can add to the truck.
- Max trailer weight = GCWR − curb − (passengers + cargo).
- Tongue weight should be about 10–15% of the loaded trailer, and it comes out of payload.
- Adding people and gear lowers the trailer weight you can safely pull below the brochure number.
How towing capacity is calculated
Three manufacturer ratings set your limits. GVWR is the most the truck alone can weigh fully loaded; GCWR is the most the truck and trailer can weigh together; and curb weight is what the empty truck weighs. Payload is GVWR minus curb — and it must absorb passengers, cargo, and the trailer's tongue weight. Whichever limit you hit first is your real-world ceiling.
Notice that passengers and cargo are subtracted twice in effect — once against payload and once against GCWR — because they reduce both what the truck can carry and what the combination can weigh.
Worked example: 7,000 / 5,500 / 13,000 lb, 600 lb load
Payload = 7,000 − 5,500 = 1,500 lb. Max trailer weight = 13,000 − 5,500 − 600 = 6,900 lb. Remaining payload = 1,500 − 600 = 900 lb, which must cover tongue weight. Suggested tongue weight = 12% × 6,900 ≈ 828 lb — comfortably inside the 900 lb left.
Hitch class by trailer and tongue weight
| Hitch class | Max trailer weight | Max tongue weight |
|---|---|---|
| Class I | 2,000 lb | 200 lb |
| Class II | 3,500 lb | 350 lb |
| Class III | 8,000 lb | 800 lb |
| Class IV | 12,000 lb | 1,200 lb |
| Class V | 20,000 lb | 2,700 lb |
Don't forget tongue weight
Tongue weight is the downward force the trailer puts on the hitch, and it counts against payload. Too little causes trailer sway; too much overloads the rear axle. Dial it in with the tongue weight calculator, and check the combined limit with the GCWR calculator before you load up.
Frequently asked questions
How do I find my truck's towing capacity?
Check the door-jamb sticker and owner's manual for GVWR and GCWR, then compute max trailer = GCWR − curb − (passengers + cargo). Never exceed the rated tow figure for your exact configuration.
GVWR vs GCWR vs payload?
GVWR is the loaded truck limit, GCWR is the truck-plus-trailer limit, and payload is GVWR − curb — everything you add, including tongue weight.
Does payload count passengers and cargo?
Yes. Payload covers passengers, cargo, accessories, and tongue weight. Subtract passengers and cargo first to see what's left for the tongue.
What reduces my towing capacity?
Passengers, cargo, fuel, accessories, and a heavy tongue all reduce payload and the GCWR margin, lowering the trailer you can safely pull.
Where do I find my GVWR?
On the certification label inside the driver's door jamb and in the owner's manual; the sticker usually lists axle ratings (GAWR) too.
Do I need a weight-distribution hitch or trailer brakes?
Most makers require a weight-distribution hitch above roughly 5,000 lb and trailer brakes above a set limit. Follow your owner's manual and local law.
Ratings come from the manufacturer's door-jamb sticker and owner's manual; tow ratings are determined under the SAE J2807 towing standard. Hitch-class figures are typical industry maximums and vary by manufacturer.
Last reviewed June 2026