Towing Safety
Gross Trailer Weight (GTW): What It Is, How to Measure It, and Why It Matters When Towing
Gross Trailer Weight (GTW) is the total weight of your trailer once it’s fully loaded, including the actual trailer’s weight and all of your cargo.
When you’re pulling a full load, safety is of the utmost importance. While you can’t control everything about the road ahead—traffic, weather, sudden stops, or curves you didn’t see coming—you can control how your rig responds when those moments happen.
Knowing your GTW and keeping it within safe limits gives you the stability, braking power, and control you need to protect yourself, your passengers, and everyone else on the road.
Below, you’ll learn what counts toward GTW, how to measure it accurately, how it compares to GVWR (your gross vehicle weight rating) and payload, and why staying within those limits matters.
What Is Gross Trailer Weight (GTW)?
Gross Trailer Weight (GTW) is the actual, real-world weight of your trailer once it’s fully loaded. That includes the empty trailer itself plus everything you’ve packed into it.
When the trailer is connected to your tow vehicle, a portion of GTW is carried on the hitch as tongue weight. Tongue weight is included in your gross trailer weight—not an additional weight added on top of it.
Tongue weight counts toward the trailer’s total weight, but it also uses up part of your truck’s payload capacity, so it affects both the trailer and the tow vehicle at the same time.
What Counts Toward Gross Trailer Weight?
Everything physically on the trailer contributes to the gross weight of the trailer, including:
- Cargo, tools, equipment, and supplies
- Coolers, camping gear, building materials, or toys
- Water, fuel, propane, and other fluids
- Pets, livestock, or people (where legal)
- Batteries, generators, racks, and aftermarket add-ons
Your trailer’s factory “dry weight” or “curb weight” is just the starting point. The GTW reflects the real load you’re actively towing.
How to Measure Gross Trailer Weight (GTW)
If your trailer doesn’t list a certified weight, or if you’ve added gear since buying it, the most accurate way to determine GTW is to weigh it yourself.
How to properly weigh your trailer:
- Load the trailer exactly as you plan to tow it.
- Visit a public scale (CAT scales, truck stops, quarries, landfills, etc.).
- Unhitch the trailer so the tow vehicle is completely off the scale.
- Roll the trailer fully onto the scale, including every wheel and the tongue jack.
- Record the number: That’s your GTW.
Alternate method (Two-Step Method):
This is a popular method because it doesn’t require unhitching the trailer.
Weigh the tow vehicle alone, then weigh the tow vehicle with the loaded trailer attached. Subtract the vehicle’s weight from the vehicle + loaded trailer to get the GTW.
Formula: Vehicle + Loaded Trailer – Vehicle = GTW.
This two-step method is not to be confused with a similar method used to get an accurate tongue weight.
If both the tow vehicle and trailer are on the scale, the added weight represents the gross trailer weight (GTW). If only the tow vehicle is on the scale with the trailer still connected, the added weight shows the tongue weight—the part carried by the hitch.
Why Gross Trailer Weight Matters When Towing
GTW determines how your trailer behaves on the road, and whether your setup stays within the limits set by the trailer manufacturer and your tow vehicle. You need to know your GTW in order to also determine the proper load weight distribution.
Placing too much of your load to one end of your trailer or the other can cause dangerous steering and control issues with your vehicle. Carrying a far too heavy load for the trailer itself can damage the trailer, and carrying too heavy a load for the vehicle’s rating can make it impossible to maintain safe driving conditions or damage the vehicle.
What’s the Difference Between Gross Trailer Weight, Gross Weight, and Curb Weight?
It’s important to understand the following distinction between GTW, gross weight, and curb weight:
- GTW measures the total weight of your trailer and everything loaded on it.
- Gross weight is the weight of everything, including your cargo, trailer, truck, and passengers.
- Curb weight is the weight of your vehicle or trailer by itself, with no added weight like passengers or cargo.
What Happens If Your Gross Trailer Weight Is Too High?
Exceeding your trailer’s weight limits can create serious safety and performance issues:
- Longer stopping distances
- Increased sway and instability
- Higher risk of tire blowouts
- Excess strain on axles, bearings, and suspension
- Reduced fuel economy
- Greater liability exposure in a crash
Overloading also increases the chance of mechanical failure and makes the entire rig harder to control.
How to Keep Your GTW Within Safe Limits
Once you know your GTW, the next step is distributing the load correctly. Aim for 10–15% of GTW as tongue weight. Too little tongue weight increases sway, and too much overloads the tow vehicle’s rear axle.
GTW can change from trip to trip, so recheck it whenever your load changes significantly. New gear, packing different seasonal work equipment, or other added cargo can change the GTW and require shifting the weight balance to ensure it’s safe for travel.
Be Weigh Safe
Gross trailer weight isn’t just a number—it’s a real-time snapshot of how your trailer is loaded. Knowing your GTW is a vital part of safe travel, protecting your equipment, and reducing the risks when you face unexpected road conditions. Having this knowledge to properly set up your gear means you enjoy the best towing experience, where you can feel you’re in total control.
FAQs
What’s the difference between GTW, GVWR, and GCWR?
GTW is the actual weight of the loaded trailer as measured on a scale. Gross vehicle weight rating (GVWR) is the maximum weight the vehicle is rated to carry, as set by the manufacturer. The GCWR is your vehicle’s gross combined vehicle weight rating, combining the entire GTW and GVWR—the total weight a vehicle can carry (including trailer and cargo), plus the vehicle’s full weight capacity, which includes its towing capacity.
Can gross trailer weight change between trips?
Yes. GTW changes anytime your cargo, fluids, or gear change. Adding firewood, filling a water tank, or loading a couple of extra coolers all shift the number.
Is GTW the same as payload or cargo capacity?
No. Payload refers to what the tow vehicle can carry in its cab and bed (including tongue weight). GTW refers to the trailer’s total loaded weight. They’re two separate measurements that both need to stay within their respective limits.
Will the subtraction method give me GTW or tongue weight?
It depends on how the trailer sits on the scale. If the entire trailer is on the scale with the tow vehicle, subtracting the tow vehicle’s solo weight gives you GTW. If only the tow vehicle is on the scale and the trailer’s axles are off it, the difference is tongue weight.
