Available Towing Capacity Calculator

Towing = GCWR − vehicle weight − passengers − payload. Stay 80% of max for safety.

Inputs

From owner's manual / specs.

Conventional: 10-15%. 5th wheel: 20-25%.

Result

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General calculation reads

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How to use this calculator

  • Find GCWR from owner manual.
  • Weigh actual passengers + cargo.
  • Set tongue %.

About this calculator

Manufacturer-rated tow capacity assumes near-empty cabin and zero cargo. Real-world tow = GCWR (gross combined weight rating) minus actual loaded vehicle weight. Tongue weight (10-15% conventional, 20-25% 5th-wheel) is supported by the vehicle so it counts against payload. Always tow 80% of computed max — leaves margin for grades, headwinds, and emergency stopping.

Frequently asked

GCWR vs. tow rating?+
GCWR = max combined truck + trailer + everyone in them. Tow rating = max trailer alone (with empty cabin). GCWR more conservative.
Tongue weight %?+
Conventional ball hitch: 10-15% of trailer. 5th wheel / gooseneck: 20-25%. Too low = sway; too high = squashes rear suspension.
Why 80%?+
Manufacturer max is for ideal conditions. 80% leaves margin for hills, wind, brake fade, and old age of vehicle.
Hitch class matters?+
Class III: 5,000 lb. IV: 10,000. V: 18,000+. Don't exceed your hitch class regardless of GCWR.
Brake controller required?+
Trailers >3,000 lb almost always need electric brakes + truck-mounted controller. Most states require if trailer brakes-equipped.

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