RV Weight & Payload Calculator
Payload against GVWR with water counted properly, tongue weight in range, and the tow-vehicle check that catches almost everyone.
The rig
People count only for a motorhome. In a towable they ride in the tow vehicle, so put them in the tow section below instead.
Hitch and tongue weight
The tow vehicle
The two traps
The sticker weight is not your weight. Dry or unloaded weight is the rig as it left the factory — no water, no propane, usually no battery, and none of the options the dealer bolted on afterwards. Every one of those comes out of the payload you thought you had. A hundred gallons across three tanks is 834 pounds on its own.
Tongue weight lands on the truck. It counts against the tow vehicle's GVWR and payload, not against its towing capacity — so a truck advertised as towing twelve thousand pounds routinely runs out of payload thousands of pounds before it runs out of towing. The headline number on the brochure is almost never the one that stops you.
Things worth knowing
- The dry weight on the sticker is the rig as it left the factory — no water, no propane, usually no battery, and none of the options the dealer added. Every one of those comes out of your payload.
- Tongue weight counts against the tow vehicle, not the trailer. A truck rated to tow 12,000 pounds regularly runs out of payload thousands of pounds before it runs out of towing capacity.
- Too little tongue weight is the dangerous direction. Below about ten per cent a trailer will sway, and sway at speed does not recover on its own.
- The only number you can trust is a scale. CAT scales cost a few dollars, weigh each axle separately, and routinely tell people something they did not want to know.
- Fifth wheels put fifteen to twenty-five per cent of their weight directly onto the truck bed. That is why they need a truck chosen for payload rather than one chosen for its towing headline.
How to use
- Enter the GVWR and the dry weight from the sticker, then everything you add.
- Set the hitch type and tongue percentage to check it is in range.
- Fill in the tow vehicle to see whether the tongue weight puts it over its own GVWR.
Frequently asked questions
What is payload capacity?
GVWR minus the dry weight — everything you are allowed to add. The catch is that dry weight is the rig as it left the factory: no water, no propane, usually no battery, and none of the dealer options.
How much does water add?
8.34 pounds a gallon. A hundred gallons across fresh, grey and black is 834 pounds, which on a small trailer is over half the payload. Travelling with the tanks near empty is usually the easiest few hundred pounds to find.
Does tongue weight count against the trailer or the truck?
The truck. It sits on the hitch, so it comes out of the tow vehicle’s GVWR and payload — not its towing capacity. A truck advertised at twelve thousand pounds of towing regularly runs out of payload thousands of pounds earlier.
What tongue weight should I aim for?
Ten to fifteen per cent of loaded trailer weight for a conventional hitch, fifteen to twenty-five for a fifth wheel. Too little is the dangerous direction: below about ten per cent a trailer will sway, and sway at speed does not recover on its own.
What is GCWR?
The maximum for the whole combination — tow vehicle and trailer together, everything in both. You can be inside it and still be over the tow vehicle’s own GVWR, which is the failure this tool checks separately.
Do I still need a scale?
Yes. This works from the numbers you type, and the sticker weight is almost never what is actually on your axles. A CAT scale costs a few dollars, weighs each axle separately, and routinely tells people something they did not want to know.
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