How Much Does A Gallon Of Oil Weigh?

The weight of crude oil ranges from approximately 6.5 lbs/US gal for light crude to 8.5 lbs/US gal for heavy crude. Oil weight is affected by changes in temperature, so the petroleum industry uses measurements that account for the fluctuations. The weight of a gallon of oil also depends on the type of oil it is. Light crude weighs less than medium which weighs less than heavy. Most common oils weigh between 7 and 8 pounds. Stored crude oil is usually around 7.2 pounds per gallon. Recycled motor oil weighs 7 pounds per gallon. Cooking oil, like olive oil, is heavier than motor oils and typically weighs around 7.6 pounds per gallon. Oils like glycerin are much heavier and can weigh up to 10.5 pounds per gallon.

A gallon of heating oil goes through some refinement before it can be used which effects its weight. Generally heating oil weighs around 8.2 pounds per gallon.

Temperature effects the weight of oil because it changes the viscosity and density of liquids. Most oils become more viscous and less dense as the temperature rises. Viscosity measures the flow of the oil. As temperatures increase, the oil becomes thinner, flows more freely and weighs less. Some types, like coconut oil, can even become a solid at room temperatures. This increases its weight.

In this article we’ll discuss how much an average gallon of oil weighs and how to calculate oils weight.

Oil Weight VS Water Weight

Most people think oil is heavier than water because its thicker. But that’s not usually the case. In most cases oil is lighter than water which is why it floats. Even most thick black heavy crude will float to the surface when spilled into water.

If you mix oil and water together the oil will float to the top. Oil and water can’t be combined even when you stir them together. The oil eventually separates and rises to the top because the oil weighs less than the water.

Crude Oil

Crude oil is usually stored in barrels which weigh about 7.2 pounds per gallon of oil.The type of oil inside the barrel effects its weight. Most crude comes in three different forms, light, medium and heavy. These terms refer to the oils weight.

In general, there’s about about a 1/4 to 1/2 pound difference in weight per gallon of oil between the different types.

Crude oil is used to create all sorts of products we use every day.

Temperature doesn’t effect crude oil as much as refined oils like motor oil or food oils. However it’s still a factor.

Here’s an interesting fact about crude oil. Even though most crude is transported in 55 gallon drums, it used to be done in 42 gallon barrels. On the US stock exchanged, oil is traded and priced per barrel which is 42 gallons of oil. Not per 55 gallon drum.

Recycled Motor Oil

Recycled motor oil weighs about 7 pounds per gallon. It’s usually strained after use which makes it thinner than new oil. The strained changes the viscosity of the oil and its therefore its weight.

Cooking Oil

In general, the oil we use to cook with weighs more per gallon than most motor oils. This is because cooking oils tend to be denser than motor oils which makes them heavier per gallon.

The average bottle of olive oil weighs about 7.6 lbs. per gallon vs around 7.2 lbs. for most new motor oils and 7 lbs. for recycled motor oil.

Vegetable oil and corn oil both weigh about 8 lbs. per gallon. Vegetable and corn oils are denser than olive or coconut oil.

The denser the oil, the more it weighs.

Coconut Oil

Coconut oil is usually packaged by its weight rather than by the pint, quart or gallons.

A pint bottle of oil usually weighs about 16 ounces, because a pint is 16 ounces. However coconut oil is a very light oil weighing only around 14 ounces per pint. To account for this, oil manufacturers price coconut oil differently than heavier cooking oils.

One gallon of coconut oil weighs approximately 7.3 pounds.

Glycerin

Glycerin is a very dense and heavy type of oil. A gallon of glycerin weighs about 10.5 pounds.

Some people don’t consider glycerin to be an oil because of its thickness but it is. When soap is rendered from fats, the glycerin oil can be separated out and used to make all sorts of beauty products. It’s rich, thick and heavy compared to other oils. And it’s supposedly very good for the skin. Because of all these traits, it’s an expensive oil.

Body Oils

Body oils that we use to care for our bodies, such as mineral oils, are very thin and light. They typically weigh less than 7 pounds per gallon.

Mineral oil isn’t as thick and dense as cooking oil, and is lighter than automobile oils. Since they’re rubbed on the skin, they need to very light or else they’d feel greasy. By refining and thinning the oil it becomes lighter.

How To Calculate The Weight Of A Gallon Of Oil

Figuring out how much a gallon oil weighs takes a bit of math.

First you have to convert the oil’s volume in gallons into weight in pounds. To do it, you need to know the density of the oil as well as the temperature.

The measurements used for this purpose are specific gravity and API gravity. We’ll discuss both below.

Specific Gravity

The National Institute of Standards uses the Baumé Scale to establish the specific gravity of liquids.

Specific gravity compares the density of a liquid to a standard liquid like water at a set temperature. To find the specific gravity of oil, divide its mass by its volume and then divide the result by the density of water at the same temperature.

Making sure the temperature is the same is very important because a liquid can change its weight at different temperatures.

Once you know the specific gravity of oil, you can calculate its weight in pounds by multiplying its specific gravity by the density of water in pounds per US gallon (lbs/US gal) at a set temperature.

The American Oil Industry uses 60°F (15.6°C) as a base temperature for measurement.
The density of water at 60°F (15.6°C) is 8.3369 lbs/US gal.

Note: In this article, all references will be based on the American Oil Industries base temperature of 60°F (15.6°C). If you live in a country that uses the metric system, you’ll have to do some additional calculations.

API Gravity

The petroleum industry uses a measurement called API gravity to measure the density of petroleum liquids.

API stands for the American Petroleum Institute (API). They established API gravity in 1921 along with the US Bureau of Standards.

Generally speaking, the higher the API gravity of oil, the lower its density. This is a useful calculation to oil companies because lower density oils cost more.

To find API gravity, divide 141.5 by the specific gravity of the oil and then subtract 131.5.

Remember, these calculations are based on the American Oil Industries standards and not the metric system.

Crude Oil Grades

In the United States, crude oil comes in different grades, which are light, medium and heavy.

Different countries and organizations can have different standards. The weight of a gallon of oil changes based on its grade. The heavier the grade, the heavier the oil.

Light, medium and heavy crude typically differ in weight from the next grade by 1/4 to 1/2 pound per gallon.

Each grade of oil’s weight is effected by the temperature its stored and weighed at.

Light Crude Oil

Light crude oil is the lightest weighing type of crude. It sells at a higher price than heavier crude because oil refineries can produce more diesel fuel and gasoline from it.

Light crude oil has a low viscosity and density. It has shorter hydrocarbon chains than heavier oils which means it can flow freely at room temperature.

Light crude has a high API gravity and low specific gravity.

The majority of crude oil refineries produce in The United States is light crude oil. It’s the most valuable and easier to turn into fuel. And it’s also the most expensive.

The Definition Of Light Crude

What defines light crude oil varies depending on who you ask. For example:

The US Energy Information Center defines light crude oil as over 40.1° API
The Louisiana Department of Natural Resources defines light crude oil as over 31.1° API
West Texas Intermediate (WTI) crude ranges between 37°API and 42° API (specific gravity of 0.8398 to 0.8156)
NYMEX lists the API gravity range of light crude oil for export as between 32 ° API and 42° API (specific gravity of 0.8654 to 0.8156).

Light crude oil produced in the United States is much lighter than what’s made in either Mexico or Canada. Both Canada and Mexico have lower API standards for what qualifies at light crude oil.

The government of Alberta defines it as 35 API.
The National Energy Board of Canada says light crude oil can have an API as low as 30.1°.
Pemex, a Mexican oil company, defines light crude oil at between 27° and 38° API.

The reason why the definition of light crude varies so much is money. Light crude is expensive because its easier to turn into fuel sources so everyone wants to produce it. Varying the definition of light crude makes production cheaper and easier.

Where you buy light crude effects its API and therefore its weight.

Domestic light crude has an average weight of around 6.5 lbs/US gal. However, if we measure according to the Louisiana DNR 31.1 API, that gives us a weight for light crude oil of 7.255 lbs/US gal.

Extra Light Crude

Light crude oil with very high API gravity between 42 and 50 (6.8 to 6.5 lbs/US gal) is sometimes referred to as super light or extra light.

A 48° API with a specific gravity of 0.79, would weigh 6.59 lbs/US gal.

Extra light crude is more expensive than the standard light crude. Remember, the lighter you go the more expensive the oil typically costs.

Light Crude Benchmarks

Different refiners create benchmarks for what makes their crude light. Here are a few:

North American West Texas Intermediate has a 39.6°API and weights approximately 6.895 pounds per gallon.
North Sea Brent Crude has a 38.06°API and weighs around 6.957 lbs/US gal.
Minas crude has an API of 35.
Sumatra light crude has an API of 35.
OPEC Reference Basket has an average API of 32.7.
Bonny Light has an API of 32.9
Isthmus-34 Light has an API of 33.74.
Tapis is extra light crude with an API gravity of 45.2.

Dubai Crude produced by the United Arab Emirates has an API of 31. This makes it medium crude by American standards. It weights approximately 7.259 lbs/US gal.

As you can see, where you buy your light crude has a big effect on the oil you get and how much it weighs.

Medium Crude Oil

On average, a gallon of medium crude weighs between 1/4 to 1/2 pound more than light crude.

Just as with light crude, what defines medium crude depends on who you ask. The US Energy Information Center has a much higher API definition than Mexico for example.

The US Energy Information Center defines medium crude oil as having between 40 and 30 API.
According to the Louisiana Department of Natural Resources, Medium Crude Oil has API gravity between 31.1 and 22.3
Mars blend crude, which is extracted off the coast of Louisiana, has an API gravity of 28 and a weight of 7.396 lbs/US gal.
Pemex of Mexico defines medium crude as under 27 API.

Mars blend crude is one of the four key benchmarks for US crude. They include lighter blends like Light Louisiana Sweet, WTI Houston, and WTI Midland. In general, if you buy crude here in the Unites States, you’ll be getting one of these four bends.

The average weight range for a gallon of medium crude oil is 7.255 to 7.54 lbs/US gal. Medium crude oil weighs approximately 1/4 to 1/2 pound per gallon more than light crude.

Heavy Crude Oil

Heavy crude oil is the heaviest form of crude. It weighs approximately 1/4 to 1/2 pound per gallon more than medium crude. It’s highly viscous with a low API and high specific gravity.

Heavy crude oils are cheaper because it requires more processing while producing lower amounts of gasoline and diesel. This means a higher cost to refine with less output.

As with light and medium crude oil, what defines heavy crude depends on who you ask. But the definition varies less than with other types of oil. This is probably due to it’s lower cost. What refiners really want is more expensive light crude.

Most standards define heavy crude oil as having 22 to 20 API and specific gravity of around 0.92. This translates to approximately 7.5 lbs per gallon.
The National Energy Board of Canada defines heavy crude oil having less than 25 API or specific gravity of 0.904
California heavy crude oil weighs about 7.63 lbs/US gal.
Mexican heavy crude oil weighs approximately 8.11 lbs/US ga.
West Canadian Select weighs about 7.736 lbs/US gal.

Heavy crude is a thicker, denser oil when compared to medium and light crude. This means it weighs more per gallon of oil. And as with any type of oil, the temperature effects its weight.

Extra Heavy Crude

Extra heavy crude oil has an API less than 10 or specific gravity of 1. This is equal to the density of water. At 60°F, heavy crude oil with an API of 10 will weigh around 8.3369 lbs per gallon. Any liquid with an API lower than that will sink in water.

How Much Does A Barrel Of Oil Weigh?

A 42 gallon barrel of oil used to be the standard size used to transport oil. But that’s changed and the industry now uses a 55 gallon drum. However, the 42 gallon barrel is still used as a measure of volume in the American oil industry.

On the American Stock Exchange, oil is reported in barrels. This abbreviated into the symbol bbl. 1 bbl typically equals 42 US gallons, 35 Imperial gallons, or 159 liters of oil.

When most people refer to a barrel of oil, they’re talking about the 42 gallon barrel. Which is strange because these days most oil is transported in a 55 gallon drum.

As with any oil weight measurement, how much a barrel of oil weighs depends on what type of oil is in the barrel and the temperature.

Here are a few approximate weights per 42 gallon barrel filled with different types of oil:

West Texas Intermediate oil weighs about 290 lbs.
Brent Crude weighs around 292 lbs.
Dubai Crude weighs approximately 305 lbs.
The average barrel of medium crude weighs between 305 lbs to 317 lbs based on the Louisiana DNR definition.
An average barrel of heavy crude weighs over 322 lbs.
West Canadian Select weighs about 324 lbs.
The average barrel of extra heavy crude weighs over 350 lbs.

A 42 gallon barrel is pretty much only used by the oil industry. Other industries use different size barrels to hold their liquids.

How Much Does A 55 Gallon Drum Of Oil Weigh?

The 55 gallon drum is the standard sized used to transport oil.

The drum is measured in 55 US gallons, which is equivalent to 45.8 Imperial gallons or 208 liters.

A 55 gallon drum is heavy and needs to be accounted for when transporting oil. A steel drum weighs about 40 lbs, a plastic drum around 20 lbs, and a fiber drum about 15 lbs. Steel drums are the strongest but weigh the most. They’re the standard for transporting oil because they can take some abuse without bursting.

Just as with a 42 gallon barrel of oil, the weight of a 55 gallon drum of oil depends on the type of oil it contains and the temperature.

Here are a few examples:

A 55-gallon drum of West Texas Intermediate weighs about 380 lbs.
Dubai Crude weighs about 400 lbs. per drum.
The weight of an average medium crude drum weighs between 400 lbs and 415 lbs based on the Louisiana DNR definition.
An average drum of heavy crude oil weighs over 422 lbs.
A drum of extra heavy crude can weigh over 460 lbs.

If you plan on buying oil by the 55 gallon drum, don’t forget to calculate he drums weight. Especially if you plan on using steel drums.

Final Thoughts

How much a gallon of oil weighs depends on its API gravity. The higher the oil’s API gravity, the lighter the oil weighs and the more it costs.

Lighter crude oils produce more gasoline and diesel which means producers can charge more. Its also easier to refine which saves money.

Here is a list of average oil weights per gallon:

Extra light crude weighs approximately 6.65 lbs/US gal.
Light crude weighs about 7.03 lbs/US gal.
Medium crude weighs approximately 7.398 lbs/US gal.
Heavy crude weighs around 8 lbs/US gal.
Extra heavy crude weighs about 8.5 lbs/US gal.

Remember, the temperature effects how much a gallon of oil weighs. The average weight also depends on where you buy the oil because it effects the API.

We use a wide variety of oils in our lives and not just the byproducts of crude. Oils are used as skin care, to cook our food, polish our furniture, and lubricate our engines. The weight of oil per gallon depends on the type of oil it is and its temperature.

Generally speaking, the heaviest types of oil are still lighter than water which is why they float.

Summary: How Much Does A Gallon Of Oil Weigh?

How much does a gallon of oil weigh? The weight of crude oil ranges from approximately 6.5 lbs/US gal for light crude to 8.5 lbs/US gal for heavy crude. Oil weight is affected by changes in temperature, so the petroleum industry uses measurements that account for the fluctuations. The weight of a gallon of oil also depends on the type of oil it is. Light crude weighs less than medium which weighs less than heavy. Most common oils weigh between 7 and 8 pounds. Stored crude oil is usually around 7.2 pounds per gallon. Recycled motor oil weighs 7 pounds per gallon. Cooking oil, like olive oil, is heavier than motor oils and typically weighs around 7.6 pounds per gallon. Oils like glycerin are much heavier and can weigh up to 10.5 pounds per gallon.

A gallon of heating oil goes through some refinement before it can be used which effects its weight. Generally heating oil weighs around 8.2 pounds per gallon.

If you have any questions or comments about oil, email any time.