Trailer Tow Calculator
Last updated: October 6, 2026
Your real towing capacity is the smallest of four ratings: tow rating, GCWR, payload, and hitch class. Keep tongue weight in CURT's 10–15% band of the loaded trailer weight. Read those figures from the door-jamb sticker and the owner's manual, then enter them in the calculator.
Free towing pocket card — print it.
Towing capacity calculator for truck and trailer owners.
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.
Questions for one trailer weight or ball size are in common questions.
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.
As an Amazon Associate I earn from qualifying purchases. The Amazon links below are affiliate links; they don't change the math.
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. Class III receivers on Amazon · WDH kits on Amazon
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.
Brake controllers and safety gear: proportional brake controllers on Amazon · breakaway kits on Amazon · tongue-weight scales on Amazon
What is my truck's real towing capacity?
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. Read those four figures from the door-jamb sticker and the owner's manual, then enter them in the calculator above.
Methodology & disclosure: the calculator applies the published rules of thumb on this page in your browser. It is a planning estimate, not a measured result — always verify against your truck's door-jamb sticker. Amazon links on this site are affiliate links; they do not change the math.
How much can your truck tow?
Read the door-jamb sticker and the owner's manual for that truck. The brochure maximum is not a substitute for either one. Enter the sticker figures and the loaded trailer weight in the towing capacity check. This page does not publish a payload range or a tow rating for a half-ton, a 3/4-ton, or a 1-ton.
Sourced data table + CSV: trailer hitch class and hitch ball weight ratings
Common questions, answered
How do I know if my truck can safely tow a trailer?
Check four numbers, not one: the manufacturer tow rating, the GCWR (gross combined weight rating), the payload rating, and the hitch class rating. Your loaded trailer plus a loaded truck must fit inside ALL of them. The binding limit is almost always payload — tongue weight plus passengers plus cargo eats the payload rating long before the tow rating runs out. Whatever limit is tightest is your real towing capacity.
What percentage of trailer weight should be on the tongue?
CURT's range is 10–15% of the fully loaded trailer weight. Below 10% the trailer can sway; above 15% you overload the truck's rear axle and lighten the front axle enough to hurt steering and braking. Measure on a packed, ready-to-travel trailer.
Does a weight-distribution hitch increase my towing capacity?
No. A weight-distribution (load-leveling) hitch redistributes tongue weight across all axles to restore steering and headlight aim, but it does not change your tow rating, payload rating, or GCWR. Manufacturers may credit a WDH with a higher tow rating on some models only if the truck's own documentation says so.
What gain should I set my brake controller to?
Use the brake-controller tab on this page. It prints a starting gain from this site's formula. Then follow the controller maker's instructions and the owner's manuals for the tow vehicle and the trailer. This page does not publish a gain setting or a test speed.
Guides
Towing capacity explained: tow rating vs GCWR vs payload
The four ratings, and a Ford F-150 example run through the tongue-weight and payload checks on this site.
2026 truck towing capacity chart
Maximum conventional towing and payload copied from the 2026 Ford, Ram, Chevrolet, GMC, Toyota, and Nissan guides.
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.
How to grease trailer wheel bearings
Dexter's 12-month or 12,000-mile interval, and the axle load left after tongue weight.
How to set up trailer brakes
Wisconsin's 3,000 lb line, a starting gain from this site's formula, and CURT's road test.
How to hook up a trailer
Coupler, crossed chains, and lights, then the payload check a latched coupler does not answer.
How to choose a trailer
Loaded weight against hitch class: 500 lb of tongue fits Class 3; 1,080 lb does not.
Fifth-wheel hitches
Kingpin versus gooseneck ball, and why a 22 percent pin estimate is the wrong input for the 10–15 percent function.
Towing a new travel trailer
NHTSA's first-trip warnings and a payload check before the tanks you will actually leave with.
How to weigh a truck and trailer
CAT Scale platform order for a truck and trailer, and a payload check kept separate from the ticket.
Trailer sway
NHTSA's controller instruction, and what this calculator returns one point under the 10 percent floor.
RV generator size ↗
Sister pages for an RV generator: which size, 13,500 BTU air conditioning, and 15,000 BTU air conditioning.
Common questions
By trailer weight
- What size hitch for a 2,000 lb trailer?
- What size hitch for a 3,000 lb trailer?
- What size hitch for a 3,500 lb trailer?
- What size hitch for a 5,000 lb trailer?
- What size hitch for a 6,000 lb trailer?
- What size hitch for a 7,000 lb trailer?
- What size hitch for an 8,000 lb trailer?
- What size hitch for a 10,000 lb trailer?
- What size hitch for a 12,000 lb trailer?
- What size hitch for a 15,000 lb trailer?
By trailer type
- What size hitch ball for a boat trailer?
- What size hitch ball for a utility trailer?
- What size hitch ball for a travel trailer?
- What size ball for a gooseneck trailer?
Brakes
Sources & Standards
Sources for the ratings and rules cited on this page: