How Many Miles Do Semi Trucks Last? + Average Mileage (MPG)

Updated: | Author: Tyler Hilgeman | Affiliate links may be present.

Are you thinking about getting a semi-truck? Do you want to start your own trucking company? Are you wondering if the high costs of semis are worth it? Do you want to know what is a normal mpg for a semi?

Semi-trucks are built to last and tend to have a lifespan of 750,000 to 1 million miles. The average mpg for a semi is 6.5 mpg, but they can reach as high as 10 mpg. When it comes to fuel efficiency, the weight, state of the tires, and driving speed should all be taken into consideration.

Average Semi Truck Lifespan

The average lifespan of a semi-truck is quite absurd. Due to their need to be able to travel great distances, semis are built differently. As a result, the average lifespan of a semi is 750,000 to 1 million miles!

Further still, there have been some semis that have lasted to the 2 to 4 million mile mark! The long lifespan of a semi has to do with two main factors. For one, typically, semis have a diesel engine, and secondly, regular maintenance is key to their longevity.

Diesel Vs Gas

Diesel engines are built with heavy-duty parts that are more gear-driven — which allows for easy replacement and repair of parts. Diesel engines are also less likely to overheat, which is critical when driving long distances.

Diesel fuel is also a big plus as it has the consistency of light oil which is better for the engine over time.

While diesel engines can be a bit more expensive to maintain and are more expensive to build, they are more than worth it in semis as longevity is key in long-distance vehicles.

Proper Maintenance

Another reason why semis last so long is that they constantly have proper maintenance done on them.

Owners of semis are actually required to do thorough maintenance checks. The Code of Federal Regulations lists everything that must be inspected, repaired, and maintained for all motor vehicles that are used for business purposes.

This includes more serious maintenance like making sure everything is properly lubricated, checking the brakes, and the steering mechanism. It also includes less serious maintenance like checking the window wipers and the horn.

These routine checks may seem like a pain, but they ensure that the semi is in working order. As a result, semis are always in prime shape and anything that might cause problems “down the road” is taken care of right away.

How Many Miles Does an Average Truck Driver Drive a Year?

The average truck driver drives 45,000 miles a year. As a result, the average semi lasts around 15 to 16 years. However, some semi-truck drives are capable of driving as much as 125,000 miles a year!

To put this in perspective, the average person drives around 10,000 to 15,000 miles a year.

While a semi can last around 15 to 16 years under normal use, most major companies will sell their semis at the 500,000-mile mark. This comes out to be around 10 to 12 years of use.

Major companies sell their semis at the 500,000 mark to safeguard against any possible major repairs that might come up as the semi nears its end.

Average Semi-truck MPG (Range of a Semi-truck)

The average range of a semi is 2,000 miles with the typical 300-gallon tank or around 1,600 miles for a 240-gallon tank.

However, because diesel will expand or contract depending on the environment, the fuel tanks are usually not filled up to full capacity. Generally, for safety, the tanks are filled up 95% of the way which leaves enough room if the diesel fuel were to expand.

While semis can range from 4 to 10 mpg, the average semi gets 6.5 mpg — but it can get as low as 3 mpg when driving uphill.

On another note, the range of a semi can increase after “break-in.” Break-in is usually said to be around the 50,000-mile mark. At that point, many trucks will have better fuel efficiency.

At 6.5 mpg, fuel efficiency is key as the average semi can cost as much as $1,200 to fill up at $4 a gallon. As a result, special care is taken to conserve as much fuel as possible.

Conserving Fuel

When it comes to conserving fuel, tires can play a big part in fuel efficiency. Over and under-inflated tires are less fuel-efficient.

Also, worn-down tires have less traction which results in more energy loss and therefore more power needed to produce the same result. So, having a good set of tires is an important part when considering fuel efficiency.

Semi-truck drivers, also, pay attention to the amount of weight they are carrying. The average semi-truck can carry up to 80,000 lbs; however, the more weight, the less fuel-efficient. So, semi-truck drivers make sure to carry only what is needed.

Traveling faster than necessary can use up more fuel than necessary. As a result, consideration of speed may be taken into account.

There is also the matter of staying in the highest gear when possible, so as not to make the engine work harder than needed and therefore use more fuel.

Lastly, total efficiency, not just weight, is key. So, when it comes to carrying a full load or a half of a load, the semi-truck driver will always opt to carry the full load.

How Far Can a Semi Go on Empty?

Considering the semi’s typical 300-gallon tank, the average semi can run for a decent about of time when on “empty.” The average semi can run for another 200 miles when on empty!

To put this in perspective, the average car can run another 45 miles when its tank is “empty.” While each semi is different and it is not recommended that you test the limits of your semi, there is no need to panic if you see that your tank is “empty.”

However, it is not great when a diesel engine runs out of diesel. This is because diesel lubricates the engine which keeps everything running smoothly. On the other hand, the absence of diesel can result in unneeded engine wear.

So, it is not worth the risk of running on empty for too long.

How Fast Is a Semi-truck?

While semi-trucks do have a big engine, they are not meant for racing, and they typically have a governor on them. Each state has its own rules; however, 65 mph is usually the standard.

This is where a problem arises. As any reasonable person understands, the only thing better than a big truck is a big truck that is fast. Thankfully, the world has Americans.

Americans have solved the problem of slow semis by practically strapping a rocket engine to the back of one.

The fastest semi in the world has three jet engines strapped to it. As a result, it can reach speeds up to 376 mph!!! Ironically, while there is a very fast semi called “Super Shockwave” this semi is just called “Shockwave.”

Despite its weight and lack of aerodynamics when compared to other vehicles, Shockwave’s pure power makes it faster than the fastest truck and the fastest car in the world.

When it comes to road-legal semi-trucks, there is Tesla’s electric semi which can reach the 100 mph mark all the way to Volvo’s “Iron Knight” which can reach the 171-mph mark.

Final Thoughts

Semis are built for long distant travel, heavy loads, and continuous use. So, they are built with heavy-duty parts and the ability for conducting easy maintenance in mind.

As a result, semis are long-lasting behemoths of the road that can take on about any challenge, including taking the record for one of the fastest vehicles in the world.

About Tyler Hilgeman

Tyler is an automotive and DIY research writer. He revels in saved money from DIY jobs and screeches at “cheap” estimates from auto body and mechanic shops. Part of his life’s work is to create a better world where automobiles are more understood and appreciated for who they are (R.I.P. My Beloved Toyota Camry — “Betsy” 1998-2021).

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