Towing Capacity Calculator
Check payload, tongue weight and the real limit on what you can tow.
Please note: A calculated limit, not a certified rating. Always check your vehicle’s actual door-jamb GCWR/GVWR plate and the trailer’s certified weight — modifications, altitude and towing equipment can reduce the real limit below what these figures suggest.
What the Towing Capacity Calculator does
Towing is constrained by two separate ratings, and the smaller one wins. GCWR caps the whole rig; GVWR caps the tow vehicle alone — and because tongue weight lands on the vehicle alongside your passengers and cargo, payload is usually what actually runs out first.
Formula
Payload capacity = GVWR − Curb weightPayload for tongue = Payload capacity − Passengers − CargoLimit by payload = Payload for tongue ÷ Tongue weight %Limit by GCWR = GCWR − Curb − Passengers − Cargo
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Gross combined weight rating (GCWR) | number | Yes | Accepts 0 or more. |
| Gross vehicle weight rating (GVWR) | number | Yes | Accepts 0 or more. |
| Vehicle curb weight | number | Yes | Accepts 0 or more. |
| Weight unit | one of 2 options | Yes | — |
| Passenger weight | number | Optional | Accepts 0 or more. |
| Cargo in the vehicle | number | Optional | Accepts 0 or more. |
| Tongue weight | % | Yes | Conventional trailers run 10–15%; fifth wheels 15–25%. |
| Actual trailer weight | number | Optional | Optional — checks a specific trailer against the limits. Accepts 0 or more. |
How to use it
- Choose Weight unit.
- Enter Gross combined weight rating (GCWR), Gross vehicle weight rating (GVWR), Vehicle curb weight and Tongue weight.
- Optionally add Passenger weight, Cargo in the vehicle and Actual trailer weight.
- Select Calculate.
Worked example
A truck with a 14,000 lb GCWR, 7,000 lb GVWR and 5,500 lb curb weight, carrying 400 lb of passengers and 300 lb of cargo, at 12% tongue weight.
- GCWR
- 14,000 lb
- GVWR
- 7,000 lb
- Curb
- 5,500 lb
- Passengers
- 400 lb
- Cargo
- 300 lb
GCWR allows 7,800 lb, but payload only leaves 800 lb for tongue weight — so at 12% the real limit is 6,667 lb. Payload binds, not GCWR.
Frequently asked questions
Why is my real towing limit lower than the advertised figure?
Advertised capacity assumes a bare vehicle with just a driver. Every passenger and every pound of cargo comes out of the same payload that tongue weight needs.
What tongue weight should I aim for?
10–15% of trailer weight for a conventional hitch, 15–25% for a fifth wheel. Too light and the trailer sways dangerously at speed.