RV weight ratings are an alphabet soup: GVWR, GCWR, GAWR, UVW, CCC, payload, tongue weight. Most RVers have seen the stickers and could not confidently explain what each number means, where to find it, or why going over even one of them turns a routine tow into an unsafe and uninsured one. This guide breaks down every rating in plain English, using the US terminology you will find on your certification labels.
If you are coming from an Australian or British background, the concepts map directly onto ATM, GTM, GVM, and GCM — the names differ, the physics do not. Our Australian weight ratings guide covers the equivalents.
The Ratings on Your Tow Vehicle
Curb Weight is your truck or SUV as it sits from the factory with fluids and a full tank of fuel, but no passengers, cargo, or hitch load. It is the baseline everything else builds on.
GVWR (Gross Vehicle Weight Rating) is the maximum your tow vehicle is allowed to weigh, fully loaded. That includes curb weight plus every passenger, everything in the bed or cargo area, every accessory, and — critically — the tongue weight of whatever you are towing. Exceed GVWR and you are operating an overloaded vehicle.
Payload Capacity is GVWR minus curb weight: how much you can add before you hit the limit. This is the number that surprises people. A half-ton pickup might advertise a big tow rating but have a payload of only 1,500–1,800 lbs — and once you subtract passengers, gear, and a few hundred pounds of trailer tongue weight, there is less left than you would think. Your payload sticker (often a yellow label on the driver's door jamb) shows the exact figure for your specific truck.
GAWR (Gross Axle Weight Rating) is the maximum load a single axle can carry, listed separately for the front and rear axles (FR and RR). Tongue weight lands mostly on the rear axle, so it is possible to be under your GVWR overall yet over your rear GAWR — a common failure point with heavy hitch loads.
GCWR (Gross Combined Weight Rating) is the maximum combined weight of the tow vehicle and trailer, both fully loaded. This is set by the vehicle manufacturer and is the rating that ties the whole rig together.
The Ratings on Your Trailer or RV
UVW (Unloaded Vehicle Weight), sometimes called dry weight, is the RV as built by the factory — no fresh water, no propane, no cargo, no passengers. Like a published dry weight anywhere, treat it as a floor, not a real-world figure; options and dealer add-ons push actual weight higher.
GVWR (of the trailer) is the maximum the loaded trailer is allowed to weigh, including everything you put in it. For a travel trailer or fifth-wheel this is the equivalent of the tow vehicle's GVWR — its own ceiling.
CCC (Cargo Carrying Capacity) — sometimes shown as NCC (Net Carrying Capacity) — is how much you can actually load: GVWR minus UVW, minus the weight of full fresh water and full propane. This is your true budget for gear, food, and everything else. Water is the sneaky one: fresh water weighs about 8.3 lbs per gallon, so a 50-gallon tank is over 400 lbs of your capacity gone before you pack a single thing.
GTW (Gross Trailer Weight) is what your trailer actually weighs, loaded, at any given moment — the number you compare against the trailer's GVWR.
Tongue Weight (TW) is the downward force the trailer places on the hitch. For a conventional travel trailer it should be roughly 10–15% of the loaded trailer weight; for a fifth-wheel, the pin weight runs higher, around 15–25%. Too little tongue weight causes dangerous trailer sway; too much overloads the tow vehicle's rear axle and lightens the steering. Tongue weight transfers onto the tow vehicle and counts against its GVWR and rear GAWR.
The Rating That Catches People: GCWR
Here is the trap that snares more RVers than any other. GCWR is not simply your tow vehicle's GVWR plus your trailer's GVWR. In many trucks, the GCWR is less than the two added together — which means you cannot legally max out both at once.
Say your truck has a GVWR of 7,000 lbs and a tow rating that suggests a big trailer, but a GCWR of 16,000 lbs. Load the truck to its full 7,000 lbs and you have only 9,000 lbs left for the trailer — regardless of what the trailer's own GVWR allows. You can be under your truck's GVWR and under the trailer's GVWR individually, and still be over GCWR in combination. Always check the combined number.
Where to Find Your Numbers
Your tow vehicle's GVWR and GAWR are on the federal certification label in the driver's door jamb; the payload figure is on the yellow tire-and-loading sticker nearby; GCWR and tow rating are in the owner's manual or towing guide for your exact configuration. Your RV's GVWR, GAWR, UVW, and CCC are on the manufacturer's weight label, often inside a cabinet door or near the entry. If your vehicle has been modified, use the updated ratings from the modifier, not the factory figures.
What Happens If You Exceed a Rating
Going over any weight rating has real consequences. Overloaded tires run hotter and fail sooner — weight-related blowouts are a leading cause of RV highway incidents. Overloaded brakes take longer to stop and fade faster on grades. An overloaded rear axle lightens the front wheels, dulling steering and lengthening stopping distance. And in a crash, operating over your ratings can give an insurer grounds to challenge a claim. None of these failure modes give much warning; they tend to show up suddenly, at speed, on a hot day.
How to Confirm Your Real Weights
Calculations get you close, but the definitive check is a scale. In the US, a CAT Scale at a truck stop lets you weigh your loaded rig — the tow vehicle, the trailer axles, and the combination — for a small fee, giving you real numbers to compare against every rating. Load the rig the way you actually travel before you weigh it.
Ready2Tow builds your full weight picture from your specifications: enter your ratings and payload and it checks GVWR, GCWR, GAWR, tongue weight, and per-axle loads against their limits, using US terminology (GVWR, front/rear GAWR, tire size) for the US market. Colour-coded results show what is safe and what needs attention, and it flags the GCWR combination trap that individual checks miss. It performs a point-in-time calculation on the figures you enter — it does not replace weighing at a scale. See the feature list for everything it covers; the Free tier gives you a pass-or-fail check at no cost. If your trailer might already be over, our guide on what to do about an overweight rig covers the fixes.
Ready2Tow provides weight and tyre pressure calculations as a guide only. It does not replace professional weighing services or qualified technicians. Always verify your weights at a certified scale before towing.
