How much does #2 diesel weigh per gallon?

Diesel fuel is commonly used for transportation, heating, and electricity generation. Diesel comes in different grades, with #2 diesel being one of the most common types used. When dealing with large quantities of fuel, it is important to understand how much diesel fuel weighs per gallon. Knowing the density and weight per gallon allows for accurate measurements and calculations regarding fuel efficiency, storage, and transportation. This article will provide a comprehensive overview of how much #2 diesel fuel weighs per gallon.

What is #2 Diesel Fuel?

Diesel is a type of fuel derived from crude oil that is used in high-compression internal combustion engines. There are several different grades and types of diesel fuel, categorized by their chemical composition and intended usage. #2 diesel, sometimes referred to as #2 distillate oil or #2 fuel oil, is a common grade of diesel fuel used for a variety of applications.

#2 diesel fuel has certain characteristics that distinguish it from other diesel grades:

– It has a lower viscosity and volatility compared to #1 diesel and kerosene. This makes #2 diesel more suitable for modern diesel engines.

– It contains slightly higher levels of sulfur compared to lighter diesel grades.

– It has a higher cetane number, measuring around 40-50. Cetane number is related to the fuel’s ignition properties.

– Its applications include transportation, home heating oil, agriculture, industrial power generation, and marine engines.

– It has a density of about 0.85 g/mL.

So in summary, #2 diesel is a mid-weight distillate fuel with moderate viscosity and volatility for use in various diesel engine applications. Understanding the density and weight of #2 diesel per gallon is useful for measuring usage and making conversions.

Diesel Fuel Density

The density of a substance refers to its mass per unit volume. For liquid fuels like diesel, density is typically measured in grams per milliliter (g/mL) or grams per cubic centimeter (g/cm^3). Diesel density can vary slightly depending on factors like purity, additives, temperature, and measurement standards.

Typical density ranges for #2 diesel fuel are:

– 0.832 – 0.876 g/mL at 15°C (60°F)
– 0.82 – 0.88 g/mL at 20°C (68°F)

According to ASTM standards, acceptable density for #2 diesel fuel oil is between 0.8165-0.876 g/mL at 15°C.

As temperature increases, the density decreases slightly. So density measurements for fuel should be corrected to standard reference temperatures when accuracy is important.

The conversion between density, volume, and mass is:

Density = Mass / Volume

So for any volume measurement of diesel fuel, we can calculate the mass if we know the density.

Weight of #2 Diesel Fuel per Gallon

Now that we know the typical density range for #2 diesel in g/mL, we can calculate the weight in pounds per gallon.

There are 3.785 liters per US gallon. At 0.85 g/mL density, one gallon of diesel fuel weighs:

0.85 g/mL * 3.785 L/gal * (1 kg / 1000 g) * (2.205 lb/kg) = 7.05 pounds/gallon

This can be rounded up to 7.1 lbs/gal for quick reference.

So for density in the range of 0.82 – 0.88 g/mL, the weight per gallon would be:

– 6.8 – 7.3 lbs/gal at 20°C
– 6.9 – 7.4 lbs/gal at 15°C

Here’s a summary table of approximate #2 diesel fuel weight per gallon:

Temperature Density Range (g/mL) Weight per Gallon (lbs)
15°C (59°F) 0.832 – 0.876 6.9 – 7.4
20°C (68°F) 0.82 – 0.88 6.8 – 7.3
60°F (15.6°C) 0.85 7.1

As a rule of thumb, #2 diesel weighs about 7.1 lbs per gallon at typical standard temperatures. This weight per gallon is useful for calculating things like:

– Fuel consumption in lbs or tons for transportation applications
– Fuel storage tank capacities
– Converting between volume and mass units
– Estimating shipping weights for fuel quantities

So for any quantity in gallons, we can multiply by 7.1 lbs/gal to determine the equivalent weight in pounds.

Diesel Fuel Weight Per Liter

The weight of diesel fuel per liter can also be useful for metric conversions.

With density of 0.85 g/mL, one liter of diesel fuel weighs:

0.85 g/mL * (1 kg / 1000 g) = 0.85 kg/L

Converting to pounds:
0.85 kg/L * (2.205 lb/kg) = 1.87 lbs/L

So the approximate weight of #2 diesel fuel per liter is 1.9 lbs/L or 0.85 kg/L.

Again this varies slightly with density and temperature between about 1.8 – 2 lbs/L.

Calculating Fuel Weights in Tanks or Containers

Knowing the weight per gallon or liter allows us to calculate total fuel weight in different sized tanks, barrels, or container volumes.

For example, say we need to know the total weight of a 500 gallon diesel storage tank when full.

Using our weight per gallon figure, we can simply multiply:

500 gal * 7.1 lbs/gal = 3,550 lbs

For a metric example, if a tank holds 2500 liters of diesel fuel, the total mass would be:

2500 L * 0.85 kg/L = 2,125 kg

This demonstrates how using the per unit weight of diesel makes it easy to determine fuel quantities for inventory management, transportation weights, and more.

Density vs Weight Per Volume

While density and weight per volume are related concepts, there is a slight distinction:

– Density tells us the mass contained in a standard unit volume – e.g. grams per milliliter. Density does not change with quantity.

– Weight per volume tells us the typical real weight for a practical volume amount. For diesel fuel, using weight per gallon or liter is convenient for real-world calculations.

Density is an intrinsic property of the fluid that does not depend on the total quantity. Weight per volume takes the density and converts it into a practical weight unit for set amounts like gallons or liters.

So density provides the basic relationship, while weight per volume gives a practical number to use for weighing quantities of fuel.

Other Factors Affecting Diesel Fuel Weight

There are some additional variables that can influence the actual weight per volume of diesel fuel:

– Temperature – As mentioned, fuel density and weight decreases slightly as temperature rises. For highest accuracy, density should be measured at standard reference conditions.

– Impurities – Contaminants or water diluted in the fuel can alter its density and weight per volume. High purity fuel will conform closest to standard density specs.

– Measurement Accuracy – Small differences in density measurement, volume quantification, and weight calibration can introduce variability. Precise methodology is required for most accurate figures.

– Fuel Standards – Diesel properties and composition can show some variation between geographic regions. For example, European diesel fuel standards differ somewhat from US standards, which can affect density.

For most practical everyday purposes, using the approximate weight per gallon or liter values provides sufficient accuracy. But when precision is vital, these factors should be taken into account.

Weight vs Volume for Fuel Economy

Both volume and weight are important considerations for calculating fuel economy in diesel engines. Volumetric fuel consumption is typically measured in gallons per mile or liters per 100 kilometers. This quantifies how much fuel volume is consumed over a distance traveled.

However, the actual work performed by an engine depends on the mass of fuel combusted, not just volume. By using fuel weight, metrics like mpg can be standardized based on energy content.

Heavier fuels contain more energy per gallon compared to lighter fuels. Diesel fuel provides about 147,000 BTU per gallon, versus 125,000 BTU for gasoline. So a gallon of diesel fuel can actually provide more mileage in a heavy vehicle than a gallon of gasoline.

Looking at fuel economy in terms of weight per distance traveled, such as lbs per mile or kg per km, can compensate for density differences between fuel types. This allows for an equal energy-based comparison.

Diesel Fuel Prices Per Gallon vs Per Pound

Retail fuel prices are generally shown on a volume basis, such as dollars per gallon. But with significant weight differences between fuels, looking at price per pound also provides useful perspective.

Given #2 diesel weighs about 7.1 lbs per gallon and gasoline weighs around 6.3 lbs per gallon, we can also calculate fuel costs on a weight basis:

– If diesel is $5 per gallon, the per pound price is $5 / 7.1 lbs = $0.70 per lb

– If gasoline is $3 per gallon, the per pound price is $3 / 6.3 lbs = $0.48 per lb

What this shows is that despite the higher price per gallon, diesel fuel often costs less per pound. This reflects the higher energy density and mileage capability of diesel fuel for its weight.

Diesel engines are also generally more fuel efficient in terms of power delivered per unit of fuel consumed. So even at a higher upfront price per gallon, diesel-powered vehicles can provide lower costs for heavy-duty transportation when considering the work performed per pound of fuel burned.

Fuel Storage and Handling Considerations

Knowing fuel weights is also useful for safe storage and handling. Diesel fuel requires storage tanks, piping, pumps, and other equipment to be robust enough to safely contain its weight. Proper filling limits must be observed to avoid overloading or failure.

For larger volumes like bulk storage tanks, the considerable fuel weight when filled requires structural supports and containment measures. Piping flow rates also rely on calculating pressure drops and pump capacities based on liquid weight in addition to viscosity.

Material compatibility is also critical for diesel storage. Certain plastics and rubbers can be degraded by diesel fuel, so appropriate metals, fiberglass, or HDPE materials should be utilized.

Staff responsible for fuel loading and inventory control should be trained on accurate quantity measurement, density checking, and weight procedures to ensure safety and prevent leaks or spills.

Transportation and Shipping Considerations

Fuel weight is a major logistical factor in transportation operations. When moving bulk amounts by truck, rail, pipeline or barge, the deadweight tonnage capacity must be adequate for the total fuel load.

For trucks, both gross vehicle weight ratings and axle weight limits must be observed to comply with highway laws and prevent accidents. Exceeding truck weight capacities risks spills or damage to vehicles and roads.

Fuel delivery paperwork usually indicates weight along with volume to provide proper documentation and compliance. Fuel weights impact logistics networks related to routing, loading times, energy usage, pricing, and more.

Understanding weight per gallon allows transportation managers to optimize the movement of inventory. It also aids in properly weighing fuel carriers like tanker trucks for registration purposes.

Environmental Impacts

In addition to direct economic considerations, diesel fuel weight is relevant for evaluating environmental impacts of transportation and equipment.

Heavier fuels like diesel mean more weight is being transported for the same energy content as lighter fuels. This results in higher greenhouse gas emissions and energy usage to move each pound of fuel to end users.

However, newer diesel engines can provide superior fuel efficiency and lower emissions compared to other engine types. Overall life cycle and equipment usage profiles determine the net environmental tradeoffs between fuel options.

Analyzing fuel weights at scales ranging from single vehicles to national supply chains provides helpful data for assessing sustainability. It highlights opportunities such as minimizing deadhead miles for empty trucks, evaluating fuel manufacturing methods, and right-sizing equipment.


In summary, #2 diesel fuel has an approximate density of 0.85 g/mL and weight of 7.1 lbs per gallon. This provides a handy conversion factor for calculating fuel quantities by weight or volume in any application. Fuel weights directly impact transportation economics, logistics, vehicle performance, safety, and environmental effects. As diesel remains a prominent fuel worldwide, understanding its weight characteristics per unit volume is essential knowledge for many industries.

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