Gross combined weight rating calculator
GCWR Calculator
Use this GCWR calculator to check whether your loaded tow vehicle and loaded trailer stay within the manufacturer’s Gross Combined Weight Rating. Enter your GCWR, curb weight, passengers, cargo and trailer weight to see your gross combined weight and the margin left under the rating.
Which number does GCWR take away from?
GCWR is a ceiling on the whole rig, not a separate allowance for the trailer. Every passenger, toolbox and gallon of fuel you add to the tow vehicle is a pound you can no longer put behind it. That is the trade this calculator makes visible: enter your figures and it reports what is left after the truck has taken its share.
One trap it avoids: tongue weight is part of the trailer’s own weight. It moves onto the truck’s axles when you hitch up, but the scale still weighs it once, so it is counted once here.
Enter GCWR and loaded trip weight
Ratings
Owner’s manual towing chart or the manufacturer towing guide.
Door-jamb label. Adds the tow rating at full payload: GCWR − GVWR.
Tow vehicle
6,000 lb before hitchingDoor sticker, owner’s manual or a scale ticket — not GVWR minus payload.
Bed cover, toolbox, weight-distribution hitch head and bars.
Trailer
7,500 lbScale weight, or dry weight plus water, propane, batteries and gear.
Already inside the trailer weight. Used only for the on-the-truck figure.
GCWR results
Remaining GCWR
1,500lb
13,500 of 15,000 lb · 90%
Within GCWR
- Tow vehicle before hitching5,300 curb + 700 passengers and cargo + 0 accessories and hitch
- 6,000 lb
- Loaded trailerIts 900 lb tongue weight included, not added again
- 7,500 lb
- Gross combined weight
- 13,500 lb
If gross combined weight exceeds GCWR, the setup is overloaded even if the trailer is below the advertised tow rating.
- Remaining GCWR
- 1,500 lb
- Heaviest trailer GCWR allows
- 9,000 lb
- Tow rating at full payload (GCWR − GVWR)
- 8,000 lb
- Tow vehicle with tongue on it (GVWR check)
- 6,900 lb
- GCWR used percentage
- 90%
- Tow vehicle before hitching
- =curb weight + passengers + cargo + accessories/hitch hardware
- Gross combined weight
- =tow vehicle before hitching + loaded trailer weight
- Heaviest trailer GCWR allows
- =GCWR − tow vehicle before hitching
What is GCWR?
GCWR means Gross Combined Weight Rating. It is the maximum allowed combined weight of the loaded tow vehicle and loaded trailer. It includes the truck, SUV, or RV, passengers, cargo, fuel, hitch equipment, trailer, water, propane, batteries, and gear. GCWR is set by the manufacturer and is usually found in the owner’s manual towing chart, manufacturer towing guide, or dealer build sheet.
Gross combined weight rating calculator: how the math works
GCWR is a ceiling on the whole rig, so every pound you put in the truck is a pound you cannot put in the trailer. Take one vehicle — a crew-cab half-ton with a 19,500 lb GCWR, a 5,500 lb curb weight, a 90 lb weight-distribution hitch, and a published 14,000 lb tow rating — and change nothing but who is aboard:
| Who and what is in the truck | Loaded truck weight | Trailer allowed by GCWR | Which limit binds |
|---|---|---|---|
| Driver only170 lb | 5,760 lb | 13,740lb | GCWR |
| Two adults, light gear340 lb + 100 lb | 6,030 lb | 13,470lb | GCWR |
| Family of four600 lb + 200 lb | 6,390 lb | 13,110lb | GCWR |
| Family of four, loaded bed600 lb + 600 lb | 6,790 lb | 12,710lb | GCWR |
How to calculate towing capacity from GCWR
Heaviest trailer GCWR allows = GCWR − tow vehicle weight before hitching
Tow vehicle weight before hitching is curb weight plus passengers, cargo, accessories and hitch hardware. Tongue weight is left out on purpose: it is part of the trailer’s loaded weight, which is the figure you are solving for. As passengers and cargo increase, the trailer GCWR leaves room for decreases. GCWR alone is not enough; also check payload (where the tongue weight does count), GVWR, hitch rating, axle ratings, and trailer GVWR before towing.
GCWR vs GVWR
| Rating | What it limits | Includes | Where to find it | Towing impact |
|---|---|---|---|---|
| GCWR | Loaded tow vehicle and trailer together | Truck/SUV/RV, passengers, cargo, hitch equipment, trailer, water, propane, batteries, and gear | Owner’s manual towing chart, manufacturer towing guide, or dealer build sheet | Sets the maximum combined rig weight. |
| GVWR | One loaded vehicle | Vehicle, fuel, passengers, cargo, accessories, and tongue weight carried by that vehicle | Driver-door certification label or owner’s manual | Can limit the tow vehicle before GCWR does. |
| Payload | Weight carried by the tow vehicle | Passengers, cargo, accessories, and tongue or pin weight | Driver-door tire and loading label | Often runs out before advertised tow rating. |
| GAWR | One axle | Weight carried by the front or rear axle | Certification label or owner’s manual | Rear axle can overload from tongue weight and bed cargo. |
| Hitch rating | Receiver or hitch hardware | Maximum trailer weight and tongue weight for the hitch | Hitch label, receiver sticker, or hitch manual | The hitch can be the limiting factor even when GCWR looks safe. |
| Trailer GVWR | One loaded trailer | Trailer, cargo, water, propane, batteries, and gear | Trailer data plate or manufacturer specs | Prevents overloading trailer axles, tires, brakes, and frame. |
GCWR example for towing
- GCWR
- 15,000 lb
- Curb weight
- 5,300 lb
- Passengers/cargo/accessories
- 700 lb
- Tow vehicle before hitching
- 6,000 lb
- Heaviest trailer GCWR allows
- 9,000 lb
- Loaded trailer weight
- 7,500 lb(its 900 lb tongue weight included)
- Gross combined weight
- 6,000 + 7,500 = 13,500 lb
- Remaining GCWR
- 1,500 lb
The 900 lb tongue weight is not added again: it is part of the 7,500 lb trailer. It does land on the truck, though — 6,900 lb on the truck’s axles — so it counts in full against payload and GVWR. This setup is under GCWR, but still needs payload, rear axle rating, hitch rating, and trailer GVWR checked.
Common GCWR mistakes
- Using advertised tow rating instead of loaded truck weight.
- Forgetting passengers and cargo.
- Ignoring tongue weight on payload — or counting it twice in combined weight.
- Confusing GVWR with GCWR.
- Assuming suspension upgrades increase GCWR.
- Using dry trailer weight instead of loaded trailer weight.
- Ignoring payload even when GCWR looks safe.
- Not checking axle ratings.
Safety and source notes
For private RV and passenger-vehicle towing, enforcement and insurance outcomes vary by state, policy, and incident details. Exceeding manufacturer ratings can increase safety risk and may affect liability or claims, so verify your ratings before towing.
Some manufacturers recommend reducing tow ratings in high-altitude conditions. Check your owner’s manual or manufacturer towing guide for model-specific derating instructions.
Manufacturer ratings and federal safety labeling help define vehicle weight limits, but your owner’s manual and certification label are the practical sources for your specific vehicle.
GCWR calculator FAQ
What does GCWR mean?
GCWR means Gross Combined Weight Rating. It is the manufacturer-assigned maximum allowed weight of the loaded tow vehicle and loaded trailer together.
How do I calculate GCWR?
You do not calculate or choose GCWR. The manufacturer assigns it. You can calculate loaded combined weight by adding loaded tow vehicle weight and loaded trailer weight, then compare that total with GCWR.
Is GCWR the same as towing capacity?
No. GCWR is the combined limit for the whole rig. Towing capacity depends on GCWR minus loaded tow vehicle weight, plus payload, GVWR, hitch rating, axle ratings, and trailer GVWR.
How do I calculate towing capacity from GCWR?
Use the formula Heaviest trailer = GCWR − tow vehicle weight before hitching, where that weight is curb weight plus passengers, cargo, accessories and hitch hardware. Leave tongue weight out of it: the tongue is part of the trailer's own weight, which is the number you are solving for. Then check the answer against the tow rating, payload and hitch rating too.
Where do I find my vehicle’s GCWR?
GCWR is usually listed in the owner’s manual towing chart, manufacturer towing guide, dealer build sheet, or model-specific towing documentation.
Does tongue weight count toward GCWR?
Yes, once. Tongue weight is part of the trailer's loaded weight — the share that rests on the hitch instead of the trailer axles. Add the loaded truck (before hitching) to the full loaded trailer and the tongue is already included. Adding it to the truck and then adding the whole trailer as well counts it twice. On a CAT scale, the three axle weights of the hitched rig add up to the same gross combined weight.
What is the difference between GCWR and GVWR?
GCWR limits the loaded tow vehicle and trailer together. GVWR limits one loaded vehicle, such as the truck alone or the trailer alone.
Can I increase GCWR with upgrades?
No. Suspension, cooling, tire, or brake upgrades may affect how the vehicle feels or performs, but they do not change the manufacturer-assigned GCWR.
Can I be under GCWR but still overloaded?
Yes. A setup can be under GCWR while still exceeding payload, GVWR, rear axle rating, hitch rating, tire rating, or trailer GVWR.
Should I use GCWR or payload for towing?
Use both. GCWR checks combined truck and trailer weight, while payload checks how much weight the tow vehicle carries from passengers, cargo, accessories, and tongue or pin weight.
How do I calculate GCWR of a truck and trailer?
You do not calculate the rating — you calculate your combined weight and compare it against the rating. Add the tow vehicle's weight before hitching (curb weight plus passengers, cargo, accessories and hitch hardware) to the full loaded trailer weight. Tongue weight is already inside the trailer figure, so it is not added again. That total is your gross combined weight; the manufacturer's GCWR is the ceiling it must stay under.
What happens if you exceed GCWR?
The rig stops and steers worse than the vehicle was validated to, the transmission and engine run hotter on grades, and brakes fade sooner on long descents. Practically, exceeding GCWR also puts you outside the manufacturer's rated operating conditions, which insurers and warranty claims can take an interest in after an incident.
Does GCWR include the trailer's own weight?
Yes — GCWR covers everything moving down the road: the tow vehicle, everyone in it, all cargo and accessories, the hitch, and the trailer with its water, propane, batteries and gear. That is what makes it different from GVWR, which covers the tow vehicle alone.