Towing Capacity Calculator: GCWR and Payload Check
How much can my vehicle tow? Enter the ratings from your door sticker and manual, then the real weight of your trailer and cargo. Each limit (gross combined weight, tow rating and payload with tongue weight) is checked and the margin is shown. This is a planning check, not a safety certification. For stopping at speed with a heavy load, see the braking distance calculator.
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Formula
- Tongue weight:
trailer × tongue % - Combined weight:
curb weight + passengers and cargo + trailer - GCWR margin:
GCWR − combined weight - Tow rating margin:
tow rating − trailer - Payload margin:
payload − (passengers and cargo + tongue weight) - Heaviest trailer: the smaller of
GCWR − curb − cargo, the tow rating, and(payload − cargo) ÷ tongue %
Worked example
GCWR 15 000 lb, curb weight 5 500 lb, 600 lb of people and cargo, payload 1 600 lb, tow rating 9 000 lb, trailer 7 000 lb, tongue 12%.
- Tongue weight 840 lb. Combined weight 13 100 lb, GCWR margin 1 900 lb.
- Tow rating margin 2 000 lb.
- Payload used 600 + 840 = 1 440 lb, payload margin 160 lb.
- Heaviest trailer: min(8 900, 9 000, 8 333) = 8 333 lb. Result: pass.
Use this when
You are matching a trailer to a vehicle before buying or hitching up. Payload is often the limit that fails first, because the hitch load uses it up together with passengers and cargo. Tongue weight of roughly 10 to 15 percent of the trailer weight is a typical guideline for conventional trailers.
How it differs from nearby pages
This page compares weights with ratings. The braking distance calculator shows how far a vehicle needs to stop, but it does not model a trailer. The power to weight ratio calculator describes performance, not legal or rated limits.
Assumptions
Tongue weight is treated as part of the trailer weight. Axle ratings, hitch rating and braking limits are not checked. Always stay within the lowest rating printed for your vehicle and weigh the loaded trailer.
Common mistakes
- Using the maximum tow rating from a brochure instead of the rating for your exact configuration.
- Forgetting that tongue weight uses up payload.
- Trusting an empty trailer weight when the loaded trailer is heavier.
Frequently asked questions
How do I calculate how much I can tow?
Take the lowest of three limits: GCWR minus the loaded vehicle (15 000 − 6 100 = 8 900 lb), the vehicle's tow rating (9 000 lb), and what its payload allows once tongue weight is counted ((1 600 − 600) ÷ 0.12 = 8 333 lb). The answer here is 8 333 lb.
What is tongue weight and how much should it be?
Tongue weight is the downward force the trailer puts on the hitch. About 10 to 15% of the trailer weight is the usual guidance for conventional trailers. A 7 000 lb trailer at 12% has an 840 lb tongue weight.
Why does tongue weight count against payload?
The hitch load sits on the vehicle, so it uses up payload together with passengers and cargo. With 600 lb of people and cargo plus 840 lb of tongue weight you use 1 440 of 1 600 lb, leaving 160 lb.
Is this a substitute for the manufacturer's figures?
No. Use the ratings printed on your vehicle and in its manual, weigh the real loaded trailer, and follow the manufacturer's limits. This is a planning check, not a safety certification.
How much is the tongue weight of a 5,000 lb trailer?
At the common guideline of 10 percent, a 5,000 lb trailer has 500 lb of tongue weight, and at 12 percent it has 600 lb. With the default vehicle a 10 percent tongue leaves 500 lb of payload margin and the check passes.
What happens if the trailer is too heavy for the GCWR?
The check fails and the margin turns negative. With a 9,000 lb trailer on the default vehicle, the combined weight is 15,100 lb, which is 100 lb over the 15,000 lb limit, and the heaviest trailer allowed is 8,900 lb.
How do I check a 10,000 lb trailer on a 20,000 lb GCWR truck?
Enter 20,000 for GCWR, 6,500 for curb weight, 800 cargo, 2,000 payload, 12,000 tow rating and 10,000 trailer. The tongue is 1,200 lb and the combined weight is 17,300 lb, so GCWR margin is 2,700 lb, but payload margin is 0 lb: it passes with no spare.