How it works
The check is a simple sum compared with the rating:
Gross combined weight = loaded vehicle + loaded trailer
Margin = GCWR − gross combined weight
Up to 90% of GCWR is shown as OK, 90–100% as at the limit, and anything above GCWR as exceeding it. The loaded vehicle weight should include everyone on board, cargo, fuel and the hitch hardware.
Worked example
A truck with a GCWR of 16,000 lb weighs 6,500 lb loaded. The travel trailer weighs 7,800 lb loaded.
- Combined: 6,500 + 7,800 = 14,300 lb
- Margin: 16,000 − 14,300 = 1,700 lb (89% of GCWR)
The rig is under GCWR. Next, check payload and the rear axle, which often run out first.
Maximum trailer weight by GCWR
Assuming a loaded tow vehicle of 6,500 lb. Subtract your own vehicle weight from GCWR to get your number.
| GCWR | Max loaded trailer | 90% mark |
|---|---|---|
| 10,000 lb | 3,500 lb | 2,500 lb |
| 12,000 lb | 5,500 lb | 4,300 lb |
| 14,000 lb | 7,500 lb | 6,100 lb |
| 16,000 lb | 9,500 lb | 7,900 lb |
| 18,000 lb | 11,500 lb | 9,700 lb |
| 20,000 lb | 13,500 lb | 11,500 lb |
| 25,000 lb | 18,500 lb | 16,000 lb |
| 30,000 lb | 23,500 lb | 20,500 lb |
How to weigh your rig
- Load the vehicle and trailer as you travel: full fuel, water, people, pets and gear.
- At a certified truck scale, weigh the whole rig with each axle on its own pad if possible. That total is your gross combined weight.
- Unhitch and weigh the vehicle alone to separate vehicle and trailer weights.
- Compare each number with GCWR, GVWR, both GAWRs and the trailer GVWR.
No scale nearby? Add the curb weight to your passengers and cargo, and the trailer’s dry weight to its cargo, water and propane. The RV water and propane calculator and theboat trailer weight calculator help with the trailer side.
Common mistakes
- Using the curb weight as the vehicle weight. Passengers and cargo can add 1,000 lb or more.
- Using the trailer’s dry weight. Loaded trailers are often 1,000–2,000 lb heavier than their dry weight.
- Assuming GCWR is curb + tow rating. Manufacturers calculate each separately; do the subtraction yourself.
- Stopping at GCWR. Also check payload and towing capacity.