Vehicles of different sizes from mammoth-like commercial trucks to off-road four-wheelers benefit from diesel. Diesel fuel goes by different names across the globe – DERV (diesel-engined road vehicle) in the U.K., distillate in Australia, and Solar in Indonesia, to name a few – and there is a widespread commercial use for its several types and blends. Similarly, there are different units used to measure it. While most countries have shifted to using liters to measure fuel in general, some places and groups of enthusiasts and mechanics still prefer the old-school gallon. Now, you may be expecting the value of a gallon to be a constant number, right? Unfortunately, it isn’t – or at least, it’s not that straightforward.
How much does a gallon of diesel weigh? The weight depends on fuel grade and unit of measurement used. A U.S. gallon weighs 6.82-8.0 lbs. The U.S. dry gallon and imperial gallon weighs 7.93-9.32 lbs and 8.19-9.61 lbs, respectively. It is best to use the U.S. gallon when weighing your diesel.
Within this article, you will understand further not only cetane ratings and measurement variants but also other factors like temperature and scientific quality tests that affect how much a gallon of diesel fuel weighs.
Measuring the weight of diesel fuel per gallon can be quite tricky, as there are different types of diesel. Not to mention that the density of each kind is not constant due to several factors. However, it is now easier to determine this value, especially if you already have the density values (pound-mass per cubic foot – lbm/ft3) for the diesel type you would like to compute for. You have to get the density of that specific fuel and divide the number by either 7.48 (7.48 lbm/ft3 is the equivalent of 1 lb. per U.S. gallon), 6.23 (6.23 lbm/ft3 is the equivalent of 1 lb. per imperial gallon), or 6.43 (6.43 lbm/ft3 is the equivalent of 1 lb. per U.S. dry gallon). Scrutinize the calculators or converters that would appear in your search results online as some use pound per cubic foot (lb/ft3) to compute for the fuel weight in gallons. There is a big difference between lbm/ft3 and lb/ft3.
Why Is It Important?
Knowing the answer to the question “how much does diesel weigh per gallon?” can never be undermined. Generally, drivers need to be familiar with their equipment and axle weight when loading or fueling – this is especially true for truckers who drive vehicles subject to weight limitations. Diesel weight per gallon also affects calculating a load of fuel in a ship or tanker truck. It is essential to ensuring the correct specifications of a cylindrical tank where fuel is stored and keeping a cruise ship at an optimum trim, which helps it remain stable even in unpleasant weather. Another reason is that when you fill your tank with fuel, the vehicle’s weight increases and your fuel economy goes down, therefore reducing gas mileage. For off-roaders, this involves caring for their 4×4 or ATV, as they would not want to cause leakages or spills on their engine by loading their fuel tanks beyond its capacity.
What Affects Diesel Weight?
- Measurement Unit. While various units represent density – g/cm3, kg/L, kg/m3, lbm/ft3, or slugs/ft3 – the actual value you get is close to constant. What would cause a discrepancy in determining how much one gallon of diesel weighs is how you convert it. Are you using the U.S., British, or Canadian measurement? Are you computing for U.S. gallon, dry gallon, or an imperial gallon? Currently, there are three different measurements in use (values round off to the second decimal place): the imperial gallon (impgal = 4.55 liters), the U.S. gallon (usgal = 3.76 liters), and the U.S. dry gallon (usdrygal = 4.40 liters). Although the imperial gallon would weigh the most, the U.S. gallon is the standard used internationally.
- Temperature. It is important to note that fuel volume fluctuates with humidity, temperature, or weather change. At room temperature, diesel is below 7 lb/gal. At 32°F, it’s a little over 7 lbs. And at very high temperatures of 100°F or above, a gallon of diesel will weigh about 6.8 lbs. This variance is why the measurement of fuel density happens at standard temperatures of 15°C or 59°F. Likewise, the viscosity of diesel increases as the temperature decreases. At −19 °C (−2.2 °F) to −15 °C (5 °F), its form changes into a gel that does not only clog fuel lines and filters but also makes it a little bit heavier.
- Specific Gravity and API. It is a standard established by the American Petroleum Institute to determine the weight of petroleum relative to water and is necessary to convert diesel volume to, say, U.S. gallons. Moreover, it is an accepted field test to determine the quality and energy level of diesel fuel – the higher the API, the lower the energy; the higher the S.G., the higher the energy output. For pure biodiesel, it has a specific gravity (S.G.) of 0.88. Diesel blends with Sulfur content such as ULSD comparatively have higher values than biodiesel, contributing to its decreased weight. 2D or Number 2 diesel would range between 0.876-0.802. In general, the specific gravity of diesel fuel may vary from 0.82 to 0.90 resulting in its weight ranging from 6.85 lbs to 7.5 lbs per gallon.
- Fuel Grade. The cetane level of diesel fuel rates the ease of ignition, horsepower, and fuel economy and relates to its overall weight. When achieved through the refining process, a higher cetane number results in higher API gravity and lower density in fuel. This means that diesel in the U.K. would have a lower weight range of 6.95-7.04 lbs compared to the U.S. since the minimum cetane rating in Europe is higher than in other countries. Similar to Europe, fuel grades in Canada gear toward EN 590 standards resulting in diesel weighing less.
Different Types of Diesel
According to engineers and fuel specialists, the type of blend of diesel fuel, among other factors, may affect how much a gallon of diesel fuel weighs. And since we are determining the exact diesel fuel weight per gallon, it is crucial to understand its different classifications and weight-affecting properties.
There are three different diesel fuel classes: 1D, 2D, and 4D. The difference between them depends on viscosity (resistance of a liquid to flow), boiling point range, pour point (lowest temperature when a liquid substance will flow), and cetane rating. I went ahead and computed their pound equivalent per gallon based on their different densities (which I got from Engineering Toolbox), as follows:
|Fuel||Density @ 59°F (15°C)
– ρ –
– v –
|(kg/m3)||(lb/ft3)||(lb/usgal)||(lb/usdrygal)||(lb/impgal)||(m3/1000 kg)||(ft3 per ton)|
|EN 590 Diesel||820-845||51-53||6.82-7.08||7.93-8.24||8.19-8.51||1.18-1.22||42-43|
1D or Number 1 diesel is chemically similar to kerosene and preferred for cold weather conditions due to its lower viscosity. This diesel type includes red diesel, a winter-grade diesel intended for off-road use, mainly in tractors, off-road equipment, or home-heating oil. It is dyed red to separate it from regular diesel since red diesel is not legal on the road and not taxed like the latter.
On the other hand, 2D or Number 2 diesel is the most common form used for ordinary and warm weather conditions and has a higher viscosity than 1D. It is sometimes mixed with 1D fuel to create a competent winter fuel. In some states, a gallon of 2D diesel fuel weighs between 6.96 lbs and 6.91 lbs within the room temperature range of 59°F to 76°F. At colder temperatures like 32°F, a gallon of diesel will weigh about 7.05 lbs.
Below are examples of 2D diesel:
- Petroleum diesel, also known as fractional distillate, petrodiesel, or fossil diesel, is the most common type and goes through boiling or distillation of crude oil to remove the unusable parts.
- Synthetic diesel consists of carbonaceous material, including biomass, biogas, natural gas, coal, and many others, and typically referred to as biomass-to-liquid (BTL), gas-to-liquid (GTL) or coal-to-liquid (CTL). It also has a paraffinic kind with almost no sulfur content and very minimal aromatics content, reducing unregulated emissions of harmful gasses. DME (Dimethyl Ether) belongs to this type too and is also environment-friendly.
- Biodiesel B5 composition is 5% biodiesel and 95% regular diesel and contains a long chain of fatty acids from vegetable oil or animal fats. B5 is the only biodiesel type that meets manufacturer’s warranties and is regulated by the ASTM D6571 standard, though most engines can run on blends of up to 30%.
- Green diesel or hydrogenated oil and fats is a crossover between synthetic and biodiesel. But unlike biodiesel, it uses the process of refining and hydrogenation to turn vegetable oil and animal fats into alkanes. Many of its properties are somewhat similar to synthetic diesel.
- Ultra-low sulfur diesel (ULSD) – S15, S500, and S5000 variants were used on highways until 2006 and off-road until 2014, but now phased out due to environmental concerns. Only S15 ultra-low sulfur diesel (ULSD) remains, becoming a standard by 2014. Its more expensive variant, MK-1 (class 1 environmental diesel), is being sold in Sweden.
- Marine diesel fuel has its own set of variants. Its MGO (marine gas oil) kind is equivalent to 2D fuel made from the distillate.
Lastly, there is 4D or Number 4 diesel used for stationary units and low-/medium-speed engines like railroad locomotives and power generators that run at a relatively constant speed. 4D diesel has a higher density of 59.9 lb/ft3 or 8 pounds per gallon than 1D and 2D diesel.
Weight Limitations – A Side Story
Now that you know more about gallon variations and different diesel types and measurements, it would be worthwhile to understand how diesel weight per gallon becomes particularly significant. Most off-roaders pass up on this. But for lorry drivers (and private vehicle owners in some states), this is part of their routine. And if they are not careful in checking on their fuel diesel weight and gross vehicle weight, they can be restricted entry, with huge overweight fines, or be cited for weight limit violations.
ATVs and 4x4s
Weight limitations currently do not govern ATVs and 4x4s, which are mainly for off-road. However, issuance of driving licenses for private and some commercial vehicles have their respective gross vehicle mass (GVM) limits. In Australia, a car driving license is limited to driving vehicles up to a maximum of 4,500 kg (9,921 lbs) – termed as light vehicles. In the U.K., a standard class B driving license limits the license-holder to 3,500 kg (7,700 lbs). In the U.S., weight limitations are 6,000 and 8,500 lbs (2,722 and 3,856 kg), respectively. Some cities restrict vehicles over 6,000 lbs, while commercial vehicles over 8,500 lbs must have insurance in compliance with federal laws.
For trucks, however, the U.S. Department of Transportation has established weight limits for those operating on interstate systems, special provisions for natural gas and electric battery transports, and property-carrying units in some states since 1974. The maximum gross vehicle weight allowed is 80,000 lbs., with a 20,000-pound limit on a single axle, a 34,000-pound limit on a tandem axle, and a 42,000-pound limit on a tridem axle. For electric battery or natural gas-operated trucks, they are allowed to exceed the weight limit by 2,000 lbs. (or by 2,550 lbs if including APU allowance) to cover the vehicle’s power unit weight. A single-axle scale measures axle weight, while the gross weight is the axle weight, drive weight, and load weight (if any) combined. Commercial vehicles that weigh anywhere over 10,000 pounds will need to stop for inspection – this would include trucks that are class 3 and up, passenger or specialty vehicles, and recreational vehicles and motor coaches in Pennsylvania.
U.S. vs. U.K. vs. Canada
Although the U.K. has a weight limitation that is pretty similar to the U.S. and Canada’s is higher, these countries measure their weight limits differently – British people use tonnes while Canadians use kilograms. Additionally, gross vehicle weight is determined using different sets of scales. Some weigh stations use a single-axle scale that operates when the truck drives over it, axle by axle. Others use a one-stop scale that weighs each axle simultaneously. Then there is the weight-in-movement (WIM) scale, which is possibly the most efficient weighing method. The trucker drives over a sensor, and the gross weight is then calculated (without the driver even having to stop).
Familiarity with your state or township’s weight limit laws, the scales your weigh stations use, and how your diesel fuel weight plays a part in all of it, is crucial to keeping you out of trouble. Furthermore, considering other factors will decide the buffer you have left for diesel fuel. Ascertain whether your truck has a standard, spread, or tandem axle. Find out the location of your fuel tank if it is underneath the cab doors or the bunk. Take into account if your trailer has refrigeration.
Tip: If you find you’re nearly at your legal weight limits, remember not to load on fuel right before approaching a weigh station. Know in advance where the weigh stations are located on your route and calculate in fuel stops. Or you can unload some of your fuel in a Fuel Storage Tank (view on Amazon) and ask help from a colleague to carry them if they are not maxed out on weight.
Frequently Asked Questions
- How many pounds is 50 gallons diesel? Using U.S. gallons, 50 gallons of diesel would be equivalent to 365 lbs for a 1D diesel, 354.50 lbs for 2D, and 400 lbs for 4D – provided you measure 50 gallons at temperatures of 15°C or 59°F. I recommend using the Oregon Scientific EMR201 Indoor/Outdoor Thermometer with Wireless Remote and Blinking LED Ice Alert (view on Amazon) to check if you’re weighing diesel fuel at room temperature.
- How much does 60 gallons of diesel weigh? At temperatures of 15°C or 59°F, 60 gallons of diesel would be equivalent to 438 lbs for a 1D diesel, 425.40 lbs for 2D, and 480 lbs for 4D but may slightly change under colder or warmer temperatures. Again, I recommend using U.S. gallons, which is the standard internationally.
- What does 100 gallons of diesel weigh? One hundred gallons of diesel would be equivalent to 730 lbs for a 1D diesel, 709 lbs for 2D, and 800 lbs for 4D at temperatures of 15°C or 59°F and using the U.S. gallon as your unit of measurement.
- Is it okay to round up diesel weight per gallon to 8 lbs for scale purposes? It depends on whether you’re using the grade of diesel fuel or the unit of measurement to draw your estimate. For instance, if you base this estimate on the U.S. gallon, then 8 lbs would cover all types of diesel (1D to 4D). But if you estimate specific to let’s say a 2D diesel, then 8 lbs may not be accurate as diesel weight translates to 8.51 lbs using imperial gallon.
- What industrial fields would benefit from knowing how much does 1 gallon of diesel weigh? Truck drivers, shipping lines, storage tank facilities, resellers of refined oil and fuels, and aircraft would greatly benefit.
- Should off-road vehicle owners know how much does one gallon of diesel fuel weigh? Yes – this will help them manage their vehicle’s gas mileage and their budget on fuel! This information will also be helpful as they plan for off-road adventures during different seasons.
- Does diesel weigh more than gas? Yes, it does – due to its larger molecules and thicker substance. For comparison, diesel weighs 7.09 lbs per U.S. gallon while gas (a.k.a. gasoline or petrol) weighs only 6.25 lbs per U.S. gallon.
Conclusion – How Much Does a Gallon of Diesel Weigh?
With standards for diesel improvement and consumers being more budget-conscious and focused on fuel economy, knowing how much diesel fuel weighs has never been more valuable. Having the ability to do your mental math will help you with a lot of things – preparing for weekend trail rides, maximizing your vehicle’s fuel efficiency, and veering away from those hefty fines and overweight tickets.
Now you know how much does one gallon of diesel fuel weigh – put it to good use.
Kris is an avid off-roader and outdoor enthusiast who loves to brave the elements and take on challenging terrain. He also enjoys sharing his passion and knowledge with others so that they, too, can appreciate the ride.