Semi-Truck Length: A Guide to Truck (and Trailer) Dimensions

Semi-Truck Length: A Guide to Truck (and Trailer) Dimensions

Diesel Truck Repair | Miscellaneous | 05/16/2024
Written by Stacy Conner

18-wheeler semi-trucks are beasts. There’s no denying it.

Whether you’re operating a day cab or a semi-truck with multiple trailers, operating a truck that’s either too large (or too small) can cause a headache. And not sticking to the Federal Motor Carrier and Safety Administration’s (FMCSA) length requirements for semi trucks can land a person in hot water.

Truck drivers, owners, and operators: we understand your pain. Keeping tabs on the many different types of semi-truck dimensions is crucial for the success of your fleet operation.

Fortunately, you’ve come to the right place. We’re Equipment Experts, Tacoma, Washington’s go-to diesel truck and fleet repair shop.

With over 20 years of experience with truck repairs, preventive maintenance, and fleet management, our master diesel technicians help everyday people and businesses with all their semi-truck needs.

If you’re wondering how long a semi-truck is — or the dimensions of a semi-truck, for that matter — look no further. In this guide, we’ll walk you through everything you need to know about a semi-truck’s dimensions so you tackle your next operation with confidence and ease.

For quick numbers, semi-trucks are on average:

Ready to learn more? Let’s dive in!

What’s included in a semi truck?

A white semi-truck driving on a mountain road with snow in the background

If you’re anything like us, we once asked ourselves the question, “What do we mean exactly when talking about semi trucks?” when trying to determine the dimensions of a semi-truck.

Semi-trucks include a tractor (the cab part where the driver and passengers sit) and a trailer (where the cargo is stored). When we’re discussing the dimensions of a semi-truck, we’re referring to both the size of the tractor and trailer combined.

The dimensions of a semi-truck explained

A fleet of different colored semi-trucks all lined up.

With the above knowledge established, we can now turn to the dimensions of a semi-truck. The dimensions of a semi-truck include the following semi-truck measurements:

Let’s take a look at each in greater detail together in the next sections.

The length of a semi-truck

A picture of a semi-truck with its length on display.

Don’t mess around with a semi-truck. Seriously.

These 18-wheeler behemoths come with fixed axles and can measure up to 70 feet long (or more)! The federal government’s minimum length requirement for a semi-truck trailer is 53 feet.

But, the FMCSA has a rule stating that a truck “operating in a truck tractor-semitrailer combination in a [United States] State on December 1, 1982” can continue to operate on the road. The minimum length of a truck “grandfathered” in from December 1, 1982, and onwards is 48 feet.

In Washington, fleet drivers are allowed to operate semi-trucks that are a minimum of 48 feet in length.

Finally, to calculate the overall length of a semi-truck, a person should measure the length of the semi-truck from the middle of the rear wheel to the center of the steer.

Subsequently, if you’re considering buying or budgeting for a semi truck — or a fleet of commercial trucks or big rigs — you may want to keep the following average length measurements in mind:

The width of a semi-truck

An aerial view of a fleet of semi-trucks in a parking lot

Fortunately, when it comes to width, most semi-trucks are fairly similar. Most semi-truck trailers and tractors are about eight to eight and a half feet wide. Semi cabs are similar in width.

The eight to eight and a half feet measurement is purposeful. With these dimensions, vehicles can better fit in a standard U.S. highway lane.

The good news is that since most U.S. highway lanes are 12 feet wide, semi-trucks have plenty of wiggle room to operate. That makes everyone’s lives much easier while on the road.

The height dimensions of a semi-truck

A fish-bowl-style photo of a red semi truck in a repair shop

To place a semi-truck’s height in perspective, a large SUV is about six feet tall. With that being said, a semi-truck clocks in at a whopping 13.5 feet tall.

At 13.5 feet, semi-trucks can clear many tunnels and other roadways with overhead height limits.

Due to the height dimensions of the semi-truck, as a driver, seeing other roadside drivers can be a challenge. If you find yourself driving next to one of these 18-wheeler motor vehicles, give yourself plenty of distance between yourself and the truck.

Doing so will keep both you and the truck driver safe on the road now and in the future.

The weight dimensions of a semi-truck

A fleet of four white Peterbilt semi-trucks

We’ve discussed the total length of a semi truck, but what about its weight? At this point, you might be wondering, “How much does a semi truck weigh?”

The answer is that it depends on whether we’re talking about the laden or unladen weight of the vehicle.

The weight will differ if referring to each of the above-mentioned terms, so it’s important to clarify which of these terms we’re referring to before determining the weight — and factors affecting the weight — of the semi-truck.

Factors affecting the weight of a semi-truck

A man sitting in the front seat of a semi-truck looking at a paper on the steering wheel

The maximum weight a semi-truck can carry is 80,000 pounds. This number includes the weight of the vehicle and the cargo it’s carrying.

In terms of cargo, a semi-truck may carry anywhere between 42,000 and 48,000 pounds worth of cargo. 

Furthermore, a few other factors can affect the weight of a semi-truck, such as:

  1. Number of wheels: Each wheel can weigh upwards of 100 pounds on its own. Given that some semi-trucks have 18 wheels, your big rig could clock in at least 1,800 pounds of tire weight alone.
  2. The type of cab of your truck: Depending on the type of truck you drive, the weight of your vehicle might differ. For instance, Sleeper cabs tend to be larger than day cabs. Therefore, a semi-truck with a sleeper cab may weigh more than a day cab.
  3. The type of trailer: depending on whether you’re operating a dry van, flatbed, or reefer trailer, the weight of your vehicle may differ. The amount — and type — of freight carried can also affect the total weight of the vehicle.

In general, though, semi-tractors tend to weigh anywhere from 10,000-35,000 pounds. To give a more detailed picture of a semi-tractor’s weight, an empty 53-foot trailer weighs about 10,000 pounds without loaded cargo.

As drivers load up their vehicles, we always recommend giving your full, undivided attention when you’re securing cargo. Being safe and thorough, and having a checklist will ensure you avoid DOT violations on and off the road.

“I call Equipment Experts because I trust them…”

A team of diesel repair technicians with their arms crossed in a diagonal line while standing next to semi-trucks

“If there’s an emergency, I call Equipment Experts because I trust them. I just know that I can pick up the phone, ask for service, and move on, knowing that it’ll be handled and that I can concentrate on what I do.” – Donnie, Equipment Experts loyal customer.

Note your state’s laws on semi-truck dimensions

A person looking down at a clipboard in an office

With nearly 166.1 million private and commercial trucks registered in the U.S. as of 2021, we’d feel awful if we didn’t mention this last fact.

Fact: Each state has different laws regarding semi-truck dimensions. Each state has a different allowed overall trailer length limit depending on local regulations.

For example, in Washington state, a tractor and semitrailer that has a semitrailer length of more than 53 feet — or where the combined two trailers and tractor exceed 61 feet — can’t be driven on the road. The trailer and tractor must be under 53 feet and/or not exceed 61 feet if combined with two trailers.

Fortunately, your local diesel repair shop is likely very familiar with the ins and outs of local regulations. Don’t hesitate to reach out to them to learn how to take control of and better manage your fleet.

Take advantage of exceptional semi-truck repair services

An aerial, drone-style image of a team of people with crossed arms with semi-trucks and pickup trucks in the background

The dimensions of a semi-truck vary. For instance, a semi-truck can measure anywhere from 53 feet to 72 feet long (and sometimes 48 feet long if your truck was built on or before 1982). A few other statistics on the dimensions of a semi-truck include:

To ensure a truck stays in compliance and tip-top shape — regardless of its length or size — many truck drivers rely on expert repair technicians to help guide them with all their semi-truck-related needs.

If you’re looking for semi-truck repairs and quality fleet maintenance, we invite you to give our diesel repair technicians a call. Even if you’re not local to the Tacoma, Washington area, we’d be happy to provide you with complimentary resources from master-trained diesel technicians to help you in your journey towards better understanding the dimensions of semi-trucks (and much more).

Need to know a little bit more about us before you call? Here’s our story. We’d love to hear yours!

Contact us today for helpful diesel truck services for all your fleet needs.

FAQ about semi-truck dimensions (length, width, and more)

A diesel repair technician working on the inside of a semi-truck

How long is a semi-truck on average?

On average, most semi-trucks built after December 1, 1982, are at least 53 feet long. Depending on whether the driver drives a day cab without bed space or a sleeper cab with bed space, the length of the truck can range anywhere from 20 to 72 feet long.

What’s the average dimensions of a semi-truck?

Depending on where you live in the United States, here are the average dimensions for length, width, height, and weight of most semi-trucks.

What’s the maximum weight a semi truck can hold?

Assuming that the trailer is loaded up with cargo, the combined weight of the semi-truck tractor and trailer can’t exceed 80,000 total pounds. The total amount of cargo weight a semi-truck can hold is between 42,000 and 48,000 pounds.

Where can I learn more about semi truck dimensions?

You can check out the U.S. Department of Transportation Federal Highway Administration’s website on regulations for commercial motor vehicles, the Federal Motor Carrier Safety Administration’s (FMCSA) website, or our blog written by and for diesel truck repair technicians and enthusiasts.

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