How Much Fuel Does a Semi Truck Consume? (2024)

A typical long-haul drive can log 1,800 hours of idle time in one year. In this article, we review average semi-truck idle fuel consumption, ideal idling rpm, and truck idling laws by state.

Idling occurs when the driver leaves the truck running in a parked position. A driver might idle their vehicle if they are making a quick visit to a truck stop or stuck in traffic. They will also idle their truck in cold conditions at night when running their personal appliances, such as a TV or a microwave.

Semi Truck Idle Fuel Consumption

A semi-truck can burn 0.6 to 1.5 gallons of fuel per hour when idling, averaging around 0.8 gallons per hour. Idling can be expensive to drivers, costing them around $40-$60 a night, depending on the fuel price. The fuel used during idling takes away from the fuel needed to drive on the road. Trucking companies also lose money from idling as truck drivers must fuel up more often to replace the fuel burned from idling.

Truckers work around the cost of idle fuel consumption by using Auxiliary Power Units(APU) to supply power to their appliances without requiring them to idle the truck. An APU can provide enough power to run the air conditioning, heater, and TV without wasting as much fuel. APUs cost around $8,500 to $13,000 to purchase and install. While the upfront cost is expensive, the APUs can save the truckers money and have a Return on Investment(ROI) of about 2.5 years.

How Much Fuel Does a Semi Truck Consume? (1)

Besides costing truckers thousands of dollars a year, semi-truck idling also destroys the reputation of truck companies and the health of their drivers. The exhaust pouring into the air from a semi-truck will naturally be associated with the company on the name of that truck. These emissions are full of toxins and carcinogens that have been shown to lead to respiratory problems, cancer, and other diseases. Keeping the environment and drivers healthy not only is the right thing to do, but it also improves the image of a trucking company.

Ideal Idling RPM

While idling is not a recommended practice, it can be necessary to maintain comfortable temperatures during extreme weather conditions. To safely idle a semi-truck, it is essential to keep the Rotations Per Minute(RPM) between 900 to 1200 to ensure the engine has enough oil.

To reach this threshold while idling:

  • While the truck is on, shift into neutral
  • Turn the cruise control on
  • Click accelerator button
  • Raise RPM until you get within the range

When the RPM is too high, it causes engine wear and wastes fuel. Idling with too low of an RPM also causes frictional wear as oil does not spread properly. Raising the RPM also raises the oil pressure, which is necessary to keep the engine running smoothly.

Besides keeping the RPM in range while idling, it is also important to:

  • Crack the window for fresh air to avoid inhaling exhaust fumes
  • Check for any exhaust leaks
  • Never leave the truck unattended
  • Park the truck relative to wind flow to blow away any fumes underneath the truck

Truck Idling Laws by State

Not only is idling bad for the engine, but semi-truck idle fuel consumption is also bad for the environment. Idling a truck releases harmful chemicals and greenhouse gasses into the atmosphere that have been shown to contribute to climate change. To combat this, many states have created truck idling laws to reduce the amount of air pollution caused by trucks. These laws define how long a trucker can idle their truck and in what instances idling is allowed.

Here’s a list of States that have idling laws for truckers:

  • No idling: Wyoming
  • 3 minutes: Delaware, DC, Hawaii, New Jersey, Virginia
  • 5 minutes: California, Maine, Maryland, Massachusetts, New Hampshire, New York, Oregon, Pennsylvania, Rhode Island, Texas, Utah
  • 10 minutes: Illinois, South Carolina
  • 15 minutes: Nevada, West Virginia

Truck idling laws are also circ*mstantial and can vary depending on where you are and the nature of your idling. Laws can also change on a local level as cities can have their own set of laws pertaining to truck idling.

Semi-truck idle fuel consumption hurts both the driver and the people around them. If idling is absolutely necessary, do it for the shortest time possible, as it wastes gas, hurts the environment, and could potentially cause you legal problems.

How Much Fuel Does a Semi Truck Consume? (2024)


How Much Fuel Does a Semi Truck Consume? ›

A semi-trucks horsepower will range from 400 to 600hp. The engines of a semi-truck can hold around 15 gallons of oil. That's a big jump from the 4-6 gallons that a passenger car engine can. The average fuel efficiency of a semi truck is about 6-7 miles per gallon.

How much fuel does a semi-truck consume? ›

Semi Truck Idle Fuel Consumption

A semi-truck can burn 0.6 to 1.5 gallons of fuel per hour when idling, averaging around 0.8 gallons per hour.

What is the average fuel consumption of a truck? ›

Data on fuel consumption of trucks

Let's settle on an average of around 30 or 40 litres of diesel every 62 miles. For larger trucks with a payload of around 23.5 tonnes, the consumption can increase up to 38 litres per 62 miles.

What is a good mpg for a semi-truck? ›

On average, semi-trucks get only 6.5 miles per gallon. Their efficiency ranges wildly between 3 mpg going up hills to more than 23 mpg going downhill. But even if it were possible to plan entire routes with only downhill roads, that's not the most efficient method of improving fuel efficiency.

How many gallons does a semi-truck use? ›

When you factor in the radius of operation, a semi truck tank generally holds 120 to 150 gallons of fuel per tank, meaning that two tanks will total up to 300 gallons. Truck owners often ask this question because there are plenty of factors to consider when loading your semi with fuel.

How much gas does a truck use? ›

Calculate Your Fuel Cost
22/26 Foot Truck
Fuel TypeDieselGasoline
MPG Average86
Average Cost per Gallon$3.95$3.53
Cost per Mile$0.49$0.59
3 more rows

How much fuel does a fuel truck use? ›

Generally, a truck's average fuel efficiency is 30 to 40 litres of diesel for every 100km driven.

How do I calculate fuel consumption of my truck? ›

Fc* = Miles Driven / Amount of Fuel Used

While this is an easy-to-follow formula, it's not always the most precise way to figure out your miles per gallon. There are many factors that affect that number, including the weight of the load you're hauling, truck specs, and your driving style.

What is a good fuel consumption rate? ›

What qualifies as fuel efficient, then? Anything that is listed as less than 6-litres/100km or more than 16.5km/1-litre is considered to be pretty good. The first (and most common) reference is litres per 100km (litres/100km). This is how many litres of fuel the car needs in order to travel 100km.

What is the average gas mileage for a diesel truck? ›

Altogether, the diesel trucks averaged 18 mpg. We'll point out that we also tested a supersized Ram 2500 AEV Prospector that got 15 mpg.

How to save fuel on semi-trucks? ›

Ways to Improve Gas Mileage on A Semi-Truck
  1. Slow Down. Slowing down may be the last thing you want to do if you're trying to make good time. ...
  2. Use Cruise Control. Cruise control is your fuel-saving friend. ...
  3. Find the RPM “Sweet Spot” ...
  4. Check Tire Pressure. ...
  5. Reduce Idle Time. ...
  6. 10 Construction Zone Safety Tips for Truck Drivers.

How much does it cost to fill up a semi-truck? ›

The cost to fill up a semi-trailer truck is extremely expensive, and with prices going up seemingly on a daily basis, it gets more financially demanding with each passing day. "$700 to $1,400 to fill up, depending on the truck, the application, the size of the tanks they have," said Hunlock.

What is considered high mileage on a semi-truck? ›

High mileage for a semi trucks is between 500,000 and 1 million miles. It depends on the brand, what engine size and what horsepower you have your ECM setup to run the engine. It's different than for passenger car engines.

How much fuel does a fully loaded semi use? ›

Gas mileage range: The average gas mileage range of a semi-truck is about 6.5 miles per fuel gallon. Semi trucks with a capacity of about 300 gallons would expect to get about 2,100 miles before needing to refuel.

How far can a semi go on empty? ›

While several factors can affect this, such as the cargo, size of the engine, and style of the cab, most semi trucks can keep going for 200 miles thanks to a bigger fuel tank. The size of fuel tanks varies, but most semi trucks have two 110 to 150-gallon gas tanks, with around 30 gallons left in the fuel reserve.

Do 18 wheelers have two gas tanks? ›

Some semi-trucks have only one fuel tank while others have two tanks, both with the same capacity. Trucks that drive through remote areas will need a double tank. Generally, most drivers will only fill their fuel tanks up to 95% capacity.

How far can an 18 wheeler go on one tank of fuel average? ›

On a full tank of diesel fuel, semi-trucks typically travel around 2,000 miles (referenced for a tank of 300 gallons). Semi-trucks on average drive 54,000 miles a year. Due to the large mileage that trucks need to drive due to the nature of their work, it is important to consider what trucks have the best MPG.

How much does it cost to fill up an 18 wheeler? ›

The cost depends on the tank's capacity, which can range significantly, and the current price of fuel. Given that current diesel prices hover around $3.00 per gallon, it would cost about $360 to fill up a truck with one 120-gallon tank. Longer-haul trucks with multiple tanks could cost up to $900 to fill up.

How many gallons per mile for semi? ›

Typically a Semi uses between 4 and 7 miles to a gallon of fuel. Generally, most over the road rigs will have either two 150 gal tanks or two 200 gal. Tanks, that should give you some idea, which will range from 600 to 800 miles generally.


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