Tool
How much truck is left once the trailer is loaded
Type the ratings from the stickers, then the weight you actually put in the trailer and the cab. The page estimates loaded trailer weight, tongue or pin weight, payload left, combined weight against GCWR, and the share of towing capacity that uses.
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Waiting on the stickers
—Enter the trailer dry weight or GVWR. The loaded weight, tongue weight, payload, and combined weight fill in from there.
The assumptions, in the open
- Fresh water is 8.34 pounds per gallon. Waste water you travel with belongs in the cargo figure, not in that gallon count.
- Dry weight plus cargo plus water is the loaded trailer. Trailer GVWR is used as the loaded weight itself, because that rating already includes cargo and water.
- Tongue or pin weight is the loaded trailer times the percentage you enter. The travel-trailer default is 12.5%, the middle of the usual 10–15% band. The fifth-wheel default is 20%, the middle of the usual 15–25% band.
- Payload used is passengers and gear in the truck, plus tongue or pin weight. Hitch hardware installed after the payload sticker was printed belongs in the truck-gear number.
- Curb weight is estimated as truck GVWR minus the door-sticker payload. Combined weight adds passengers, gear, and the loaded trailer to that curb weight. Tongue weight is part of the trailer number, so it is not added again.
- The 80% line is a comfort margin on towing capacity, payload, and GCWR. Crossing it is a flag. Crossing the sticker is the stop.
- Rear axle rating is compared with tongue or pin weight only as a sanity check. The truck is already on that axle. A CAT scale is the measurement. This page does not invent the missing axle weight.
- A weight-distribution hitch moves some tongue weight toward the front axle and the trailer axles. Payload still has to hold the tongue weight. The calculator does not model that shift.
Gear that belongs with these numbers
Weight-distribution hitches, sway control, tongue-weight scales, and brake controllers are the hardware people shop once tongue weight and payload get tight. RigRank has not reviewed those categories, so this page does not link a product for them.
What the site does cover is the gear you use once the truck is doing this job. Pads and levelers for the tires and the tongue jack are in the leveling roundup, and the inches of lift are the leveling calculator. Door height changes between hitched and unhitched, which is the step calculator. The buying guide is the order for the rest of the bay. Campground length and the rest of the trip planning live on RV Camp Atlas.
Questions worth answering first
Which numbers do I type?
From the tow vehicle: towing capacity, GCWR, GVWR, payload, and the rear axle rating if the sticker prints it. Towing capacity is often in the owner's manual or on the hitch label rather than the door jamb. From the trailer VIN sticker: dry weight or the trailer GVWR. Then the cargo, the fresh water you will carry, and the people and gear in the truck. This page does not look any of that up.
What does the 80% flag mean?
It is a comfort margin on towing capacity, payload, and GCWR, so a headwind, a fuller tank, or one more passenger has somewhere to land. The calculator flags anything over 80% of those ratings even when you are still under the sticker. Anything over the sticker is a separate, louder flag. The sticker remains the limit.
Why is cargo not added to a trailer GVWR?
Trailer GVWR is the most the loaded trailer is allowed to weigh. Cargo, water, propane, and batteries are already inside it, so the calculator uses that GVWR as the loaded weight. Starting from dry weight is the better estimate of what you are actually towing. A GVWR entry is the plan for a trailer loaded all the way to its own rating.
Does this replace a CAT scale?
No. Tongue or pin weight here is the loaded trailer times a percentage, about 10–15% on a travel trailer and 15–25% on a fifth wheel, until a scale measures it. Axle loads are scale numbers too. The rear axle rating on this page is only a sanity check against tongue or pin weight, because the truck is already sitting on that axle.
What counts against payload?
The people and gear you enter, plus the tongue or pin weight. Count a weight-distribution head, a fifth-wheel hitch, or a bed toolbox when the door sticker was printed before those were installed. A weight-distribution hitch can shift some load to the front axle and the trailer axles. The tongue weight still spends payload.