About the Towing Capacity Calculator
This towing capacity calculator tells you whether a trailer is within your vehicle’s limits and what the true maximum trailer weight is once passengers, cargo and tongue weight are counted. The number in the brochure is only one of several limits: the gross vehicle weight rating (GVWR), the gross combined weight rating (GCWR) and the payload all have to be respected at the same time.
Use it when shopping for a camper or boat, when choosing a tow vehicle, or before a trip with a loaded truck bed and a full cab. People are often surprised that a pickup rated to tow 9,000 lb can only pull 7,000–8,000 lb once the family and gear are aboard, because the trailer’s tongue weight eats into payload.
Take ratings from the door-jamb sticker (Tire and Loading Information and the certification label) and the owner’s manual. The calculator is a planning aid: always follow the manufacturer’s limits, hitch ratings and any local towing laws.
With the default inputs, the max safe trailer weight (with this load) is 8,400 lb. Change any value above to recalculate instantly.
How to use the towing capacity calculator
- 1Find the tow rating, GVWR and GCWR in the owner’s manual or on the door-jamb sticker.
- 2Enter the curb weight and the weight of passengers and cargo you will carry.
- 3Enter the loaded trailer weight and its tongue weight percentage.
- 4Check the status and the maximum safe trailer weight.
- 5If you are close to a limit, reduce cargo or choose a lighter trailer.
Formula and method
Three limits apply at once. The trailer must not exceed the manufacturer’s tow rating. The truck plus everything in it plus the trailer (gross combined weight) must stay under the GCWR. And the vehicle itself — curb weight plus passengers, cargo and the trailer’s tongue weight — must stay under the GVWR, which is the same as saying the load must not exceed payload capacity (GVWR − curb weight).
Tongue weight is the share of the trailer’s weight resting on the hitch, typically 10–15% for a bumper-pull trailer. The calculator solves each limit for trailer weight and reports the smallest. It does not check axle ratings (GAWR), hitch class or tyre load ratings, which you should confirm separately.
- GVWR
- Maximum allowed weight of the loaded vehicle
- GCWR
- Maximum allowed weight of vehicle + trailer combined
- Payload
- GVWR − curb weight
- Tongue %
- Share of trailer weight carried by the hitch
Worked examples
Half-ton pickup towing a 6,000 lb camper
Payload is 7,000 − 5,000 = 2,000 lb. A 12% tongue (720 lb) plus 600 lb of cargo leaves 680 lb spare. Combined weight is 11,600 lb, 2,400 lb under GCWR. The GCWR limit (14,000 − 5,600 = 8,400 lb) is tighter than the 9,000 lb tow rating, so 8,400 lb is the real maximum.
Same truck, heavier trailer and load
An 8,500 lb trailer is under the 9,000 lb tow rating, and payload still has 80 lb to spare, but the combination weighs 14,400 lb — 400 lb over the 14,000 lb GCWR. With 900 lb aboard, the real maximum is 8,100 lb.
Mid-size SUV with a 5,000 lb boat
Payload is 1,600 lb; 500 lb of people plus a 500 lb tongue leaves 600 lb. The GCWR allows 11,500 − 4,900 = 6,600 lb of trailer, which is lower than the 7,000 lb rating, so the boat is fine with 1,600 lb to spare.
Frequently asked questions
What is the difference between GVWR and GCWR?+
GVWR is the maximum the vehicle itself may weigh, including passengers, cargo and tongue weight. GCWR is the maximum for the vehicle and trailer together. Both appear in the owner’s manual; GVWR is also on the door-jamb certification label.
How do I calculate tongue weight?+
Multiply the loaded trailer weight by the tongue percentage — usually 10–15% for a conventional trailer. A 6,000 lb trailer at 12% puts 720 lb on the hitch, and that counts against your payload.
Why can I not tow my full rated capacity?+
Tow ratings usually assume a lightly loaded vehicle with just a driver. Every pound of passengers, cargo and accessories reduces what is left under the GCWR and the payload, so the practical maximum is often lower.
Where do I find my payload capacity?+
In the US, the yellow Tire and Loading Information sticker on the driver’s door jamb states that “the combined weight of occupants and cargo should never exceed” a number — that is your payload for that specific vehicle.
Is it safe to tow at 100% of capacity?+
It is legal if every rating is met, but many experienced towers keep the trailer at 80% or less of the maximum for better braking, stability in crosswinds and less strain on hills.