A 6,000 lb travel trailer at 12% puts 720 lb on the hitch. Behind a truck rated for 9,000 lb that is 67% of capacity, inside the 80% rule, and it needs a Class III receiver.
How the towing calculator works
TowCapacityCalc multiplies the loaded trailer weight by the tongue percentage to get the tongue (or fifth-wheel pin) weight, then compares it with the usual range for the trailer type: 10–15% for a conventional bumper-pull trailer, 15–25% for a fifth wheel and 20–25% for a gooseneck. It divides the trailer weight by your towing capacity and flags anything above the 80% rule of thumb, subtracts people, cargo and tongue weight from payload, and suggests the lowest receiver hitch class rated for both the trailer and the tongue weight. Weights work in pounds or kilograms.
Receiver hitch class chart
| Class | Max trailer | Max tongue | Typical use |
|---|---|---|---|
| Class I | 2,000 lb | 200 lb | cars and small crossovers, bike racks, small utility trailers |
| Class II | 3,500 lb | 350 lb | crossovers and minivans, small boats and campers |
| Class III | 8,000 lb | 800 lb | pickups and SUVs, most travel trailers and boats |
| Class IV | 10,000 lb | 1,000 lb | full-size pickups and SUVs, larger campers |
| Class V | 20,000 lb | 2,000 lb | heavy-duty pickups, equipment and car haulers |
Ratings are typical maxima; your hitch’s label and the vehicle’s manual are the final word. The towing capacity, payload, GVWR, GCWR and axle ratings all apply at once, and the lowest one is your real limit. Weigh the loaded rig at a truck scale before a long trip.
Frequently asked questions
How do I calculate tongue weight?
Multiply the loaded trailer weight by the tongue percentage: a 5,000 lb trailer at 12% has 600 lb of tongue weight.
What is the 80% towing rule?
A rule of thumb to keep the loaded trailer at or below 80% of the vehicle’s rated towing capacity, leaving a margin for hills, wind and braking.
Does tongue weight count against payload?
Yes. Tongue or pin weight sits on the vehicle, so it is subtracted from payload along with passengers and cargo.
Is TowCapacityCalc free?
Yes, with no sign-up or ads, and your numbers stay in your browser.
Is this a substitute for my vehicle ratings?
No. It is an estimate. Always follow the owner’s manual, the door-jamb sticker and the hitch and trailer ratings, and weigh your rig at a scale.