How Much Does a Gallon of Diesel Weigh?

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Close up of a diesel sign

Diesel is one of the most widely used fuels in the world. It powers vehicles and equipment in a variety of important industries. If the weight of your vehicle or equipment is a concern, you may wonder how much a gallon of diesel weighs. 

While it’s easy to find the price of a gallon of diesel fuel, the weight of diesel can vary. Several factors can change how heavy it is.

Today, we’re taking an in-depth look at the weight of diesel to help answer any questions you might have. Let’s get started! 

What Is Diesel?

Diesel is a heavy, oil-based fuel typically derived from crude oil. It gets used in various applications, including diesel engines for cars, trucks, buses, and other vehicles. Additionally, it is a common fuel source for industrial generators, heavy equipment, and marine vessels.

It has a high-energy density, especially compared to gasoline. This allows it to produce more power without impacting efficiency as much. This efficiency is one of the primary reasons it is the fuel of choice for those hauling heavy loads.

Another unique characteristic of diesel fuel is its ignition process. Because diesel has such a high ignition point, it doesn’t rely on a spark plug to ignite the fuel like gasoline engines. 

Instead, it gets injected into a combustion chamber and mixes with the air. A piston moves forward, compressing the air and fuel to the point where it ignites.

While diesel fuel has historically gotten a bad reputation for its emissions, that’s not necessarily the case. The United States and many other countries have created strict emissions standards that have drastically reduced harmful emissions from diesel engines.

How Much Does a Gallon of Diesel Weigh?

Unfortunately, knowing the exact weight of a gallon of diesel isn’t as easy as you might think. Sure, you can say a gallon of diesel weighs around 7 pounds. However, this isn’t exact, and precision is important if you’re hauling hundreds or thousands of gallons of fuel.

The weight of a gallon of diesel depends on the fuel’s temperature and specific gravity. Any adjustment in these characteristics will also impact its weight. However, the changes don’t have a significant impact.

You can use a calculator from Aqua-Calc to do some tests. Let’s pretend you put 35 gallons of diesel into your vehicle, and it’s 21 degrees Fahrenheit.

The calculator tells us it would weigh approximately 262.36 pounds. If you have the same amount of fuel at 85 degrees Fahrenheit, it would weigh 254.87 pounds. 

If you’re only dealing with 35 gallons, the 7.49-pound difference isn’t very significant. However, fuel trucks that haul diesel to filling stations can carry around 11,000 gallons. In that same scenario, with 11,000 gallons, it would make a difference of 2,352.44 pounds. That’s a ton of weight.

How Is Diesel Fuel Different Than Regular Gas?

Diesel fuel and regular gas may serve similar functions but differ greatly, apart from how much a gallon weighs. Diesel fuel is a byproduct of crude oil from a hydrocarbon mixture. 

It is denser than gas and has a higher boiling point than water. This helps it to be more resistant to evaporation than gasoline, which can evaporate at room temperature.

Gasoline is substantially more flammable than diesel fuel. The slightest spark near a gas tank can cause a serious situation. However, the flash point for diesel is so high that tossing a lit match onto a puddle of diesel fuel would do nothing but extinguish the flame.

Another difference is that diesel is much more efficient. It has a higher energy density and a higher compression ratio. Thus, diesel vehicles are stronger and more capable and require less fuel.

If you’ve seen the price at the pump lately, you’ll likely appreciate any savings you can get.

Why Is Diesel Fuel More Expensive Than Gasoline?

While diesel fuel may be more efficient than gasoline, it costs more at the pump. Unfortunately, it’s an unavoidable part of owning a diesel vehicle. However, several factors make diesel fuel more expensive.

First, the refining process for diesel is typically more expensive than gasoline. The higher boiling point means it takes longer to remove impurities and prepare the fuel for use.

During this process, refineries improve the cetane number, which indicates how well the fuel will burn in an engine.

Another reason diesel fuel is more expensive than gasoline has to do with taxes. While the glowing light bulbs may tell you the price at the pump, they’re not telling you what’s included in that price. 

States charge a tax on both diesel and gasoline sales. While many states charge the same tax for both types, that’s not always the case.

Indiana, Pennsylvania, and Connecticut charge more per gallon for diesel than gasoline. In some states, you could pay $.20 to $.39 more in taxes per gallon.

Supply and demand can also greatly impact the price of diesel. While consumer vehicles often fill up 10 to 20 gallons at a time, semis regularly fill up hundreds of gallons at a time.

Even small changes in the diesel fuel supply can significantly impact the price at the pump.

A Diesel gas pump at a gas station

What Affects Diesel Weight?

A handful of factors affect how much a gallon of diesel weighs. Understanding them can help you know how heavy it is and help you keep an engine running smoothly. Let’s take a look!


As we showed earlier, the weight of diesel can change based on its temperature. As the temperature increases, the volume increases and its weight decreases. 

On the other hand, a decrease in temperature causes the fuel to contract and increase in weight.

It’s not uncommon for some drivers to experience mechanical issues due to these changes.

Cold weather can cause diesel fuel to become thick, which can lead to clogs in fuel lines and filters. Many drivers use fuel additives to help prevent clogs in their fuel systems. 

Keep in Mind: Have you ever thought about what would happen if you put DEF in a Diesel Tank? Click the link to find out!

Type of Diesel / Fuel Grade

Not all diesel fuel and grades are the same. Since their formulas can be very different, their weights are too. Let’s look at the most common types of diesel and how heavy they are.

Number 1 Diesel

Number 1 Diesel has a lower viscosity than other types of diesel fuel. This allows it to ignite easier and burn cleaner. This diesel generally weighs around 7.3 pounds per gallon. In addition, it isn’t nearly as energy-rich as Number 2 diesel.

It is also known as winter diesel and is typically for off-road equipment and home heating. Since it doesn’t get taxed like road fuel, you must know the rules for when and where to use it. Number 1 diesel isn’t as readily available as other types, but some rural stations carry it.

Close up of a Diesel gas pump

Number 2 Diesel

Number 2 diesel is the most common form used. It is higher in energy density and can provide tremendous power. A gallon of this type of diesel will generally weigh around 6.91 and 6.96 pounds. However, as we’ve mentioned, this can change based on the temperature and humidity levels.

Petroleum, synthetic, and ULSD are all examples of Number 2 diesel fuels. Each blend has its own characteristics that make it different from the rest. The refining process allows refineries to create different blends. 

Specific Gravity

Specific gravity (SG) measures a substance’s density relative to water. The specific gravity of water is 1.0.

As a result, any item with a specific gravity less than 1.0 is less dense than water. Additionally, any substance with a specific gravity greater than 1.0 is denser than water.

Pure biodiesel has a specific gravity of 0.88 compared to Ultra-Low Sulfur Diesel’s 0.82. ULSD minimizes the number of sulfur particles, reducing sulfur dioxide emissions. This helps avoid air pollution and respiratory problems. 

However, biodiesel comes from vegetable oils and animal fats. The various blends of biodiesel range from 5%/95% and 20%/80% of biodiesel to petroleum diesel.

ULSD is a fossil fuel, while biodiesel is a renewable fuel, which can help us reduce our dependence on fossil fuels. While ULSD is readily available at many service stations, biodiesel is not. It’s often available regionally or seasonally in some locations. 

Keep in Mind: We hate the smell of diesel on our clothes, but we figured out a few ways to get the diesel smell out of our clothes

Close up of a Diesel gas pump

Diesel Weighs More and Packs a Punch

A gallon of diesel fuel weighs more, but it tends to pack more of a punch than gasoline. This is partly due to the higher energy density of diesel fuel and its ability to contain more energy per unit. 

If you need to haul a lot of diesel fuel, knowing how much it weighs is important. You may have weight limits for your vehicle, the roads, and many others. 

It can be tough to choose between a diesel or gas engine. You must factor in weight, quantity, price, etc. However, it’s hard to beat diesel if you want to get the job done quickly and efficiently.

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