Five gallons of regular unleaded gasoline weighs roughly 30 to 31 pounds, or about 14 kilograms. That figure is not perfectly fixed because gasoline is a blend of many hydrocarbons whose proportions change with the grade, the season, and the ethanol content, all of which nudge the density up or down. The weight also shifts with temperature, so the same five gallons is slightly heavier on a cold morning than on a hot afternoon.
Where the Number Comes From
Gasoline’s density typically falls between about 720 and 775 kilograms per cubic meter, depending on the specific blend. For a standard US gallon (3.785 liters), that translates to roughly 6.0 to 6.5 pounds per gallon. Most regular unleaded gasoline sold at US pumps sits closer to the lower end of that range, around 6.1 to 6.2 pounds per gallon, putting five gallons in the neighborhood of 30.5 to 31 pounds. Premium grades and certain research-formulation gasolines can be denser. One study measuring a base gasoline used in biofuel comparisons recorded a density of 792.8 kg/m³, which works out to about 6.6 pounds per gallon and would push five gallons closer to 33 pounds.1Thermal Science and Engineering Progress. Turning biomass into gasoline biofuel: A sustainable bridge between bio-innovation and clean energy for modern engines That particular formulation sits at the heavier end of what you would encounter, but it illustrates how much the exact composition matters.
If you are trying to estimate quickly, treating gasoline as roughly 6 pounds per gallon gets you close enough for almost any practical purpose. Five gallons at 6 pounds each equals 30 pounds. The real value will be within a pound or two of that depending on exactly what came out of the pump.
How Temperature Moves the Weight
Like most liquids, gasoline expands when it heats up and contracts when it cools down. The volume in the tank stays the same, but the mass of fuel occupying that volume changes slightly. In the petroleum industry, density measurements are standardized at 60 °F (15.6 °C) precisely because the same gallon of fuel weighs a bit less on a sweltering summer day than on a freezing winter night. The change is not dramatic for everyday purposes: across the temperature swings a typical driver encounters, the weight of five gallons shifts by only a fraction of a pound. But at industrial scale, where tanker trucks move thousands of gallons, even a small density change per gallon adds up to meaningful differences in the total mass being transported.
This is also why some drivers have heard the tip to fill up in the early morning when the fuel in underground storage tanks is cooler. The idea is that cooler gasoline is denser, so you get slightly more mass per gallon. In practice, underground tanks are well insulated by the surrounding earth, and their temperature stays fairly stable regardless of the air temperature above. The savings from timing your fill-up are negligible.
Ethanol Blends and Seasonal Formulations
Most gasoline sold in the United States is E10, meaning it contains up to 10 percent ethanol by volume. Ethanol is denser than many of the lighter hydrocarbons in gasoline, so blending it in raises the overall density of the fuel slightly. E15 and E85 blends push the density a bit further. However, the effect on weight per gallon is modest, typically only a few hundredths of a pound per gallon compared to pure gasoline. What changes more noticeably is the energy content: ethanol carries less energy per unit of volume than gasoline, so higher-ethanol blends deliver fewer miles per gallon even though the liquid itself weighs about the same.
Seasonal reformulation also plays a role. Refineries produce a lighter, more volatile “summer blend” gasoline that resists excessive evaporation in hot weather and meets stricter emissions standards. Winter blends are cheaper to produce and include more of the lighter hydrocarbons that evaporate easily, which helps engines start in cold temperatures. These lighter winter blends tend to sit at the lower end of the density range, while summer blends can be slightly heavier. One study examining gasoline blends with various oxygenates noted that blend densities could be calculated reliably as a simple weighted average of the components, because the volume change from mixing was negligible, less than 0.34 percent.2Fuel. Physical properties of gasoline, isobutanol and ETBE binary blends in comparison with gasoline ethanol blends – Section: Conclusions In other words, the density of your final fuel tracks pretty linearly with what went into the mix.
Gasoline Compared to Water and Diesel
A common reference point is water, which weighs about 8.34 pounds per US gallon at room temperature. Five gallons of water tips the scale at nearly 42 pounds, which means gasoline is roughly 25 to 30 percent lighter than the same volume of water. This is why gasoline floats on water and why water contamination in a fuel tank settles to the bottom.
Diesel fuel sits on the other side. Diesel is denser than gasoline, typically around 6.9 to 7.1 pounds per gallon. Five gallons of diesel weighs somewhere around 34.5 to 35.5 pounds. If you have ever carried a five-gallon jug of diesel and then a five-gallon jug of gas, you may have noticed the diesel feels heavier, and it is, by about four or five pounds. Diesel’s higher density is part of why it packs more energy per gallon, which is one reason diesel engines tend to get better fuel economy in terms of miles per gallon despite the fuel being heavier.
How Much Fuel Weight Is in Your Tank
Knowing what a gallon of gas weighs becomes useful when you think about the total weight your vehicle carries around. A midsize sedan with a 14-gallon tank holds roughly 84 to 87 pounds of fuel when full. A full-size pickup truck with a 26-gallon tank is lugging around 156 to 162 pounds of gasoline. That is equivalent to carrying an extra adult passenger just in fuel weight.
Some drivers wonder whether keeping the tank half full instead of topping off saves enough weight to improve fuel economy. The math works out to a savings of roughly 40 to 80 pounds depending on tank size, but the impact on fuel economy is tiny. Most estimates put the effect at less than one percent improvement in miles per gallon for a typical car. You would spend more fuel making extra trips to the gas station than you would save by keeping the tank light. The scenario where fuel weight matters more is in motorsport or aircraft, where every pound counts. Race teams and pilots plan fuel loads carefully because even a few extra gallons can affect handling or range in a meaningful way.
Carrying Five Gallons by Hand
A standard five-gallon gas can, once filled, weighs about 30 to 31 pounds of fuel plus the weight of the container itself, which is typically one to two pounds for a plastic jug or somewhat more for a metal jerry can. You are looking at around 32 to 34 pounds total for a full plastic five-gallon can. That may not sound like much, but the shape of a gas can makes it awkward to carry. The weight hangs off to one side of your body, the handle forces you to grip with one hand at an angle, and the sloshing liquid shifts the center of gravity unpredictably. Carrying it any distance puts asymmetric stress on your back, shoulder, and wrist.
Research on workers who regularly lift and carry heavy containers has documented exactly these problems. A study of workers transporting heavy items like water jugs and gas cylinders found that repeated lifting caused muscle complaints and could lead to damage in joints, tendons, and ligaments, a category of injury broadly called musculoskeletal disorders.3Logic Jurnal Rancang Bangun dan Teknologi. Analysis of the Use of Ergonomic Trolley on Musculoskeletal Complaints on Worker Transporting Gallons of Water and LPG 12 Kg – Section: Results and Discussion Separate research on workers handling gas cylinders found that the majority experienced injuries to the back (34 percent), shoulders (20 percent), and knees (20 percent), with the loading postures classified as having “very harmful” effects on the musculoskeletal system in 90 percent of cases.4PubMed Central. Identification of awkward postures that cause discomfort to Liquid Petroleum Gas workers in Mumbai, India – Section: Results
For the average person carrying a gas can from the pump to a stalled car on the roadside, this is not a major injury risk from a single trip. But if you find yourself regularly hauling five-gallon cans for a generator, a boat, or lawn equipment, investing in a small hand cart or wheeled fuel caddy saves your back real wear over time. When you do carry by hand, keep the can close to your body, switch sides periodically, and avoid twisting your torso while carrying the load.
Does Gasoline Lose Weight if It Sits Around
Gasoline is a mixture of hydrocarbons with a wide range of boiling points. The lighter, more volatile components evaporate more readily, even at room temperature. If you leave a container of gasoline partially open or poorly sealed, those lighter fractions escape into the air first, and the remaining fuel gradually becomes heavier per unit of volume because the denser, higher-boiling-point components stay behind. Research on gasoline evaporation has confirmed that the light hydrocarbons evaporate easily at room temperature while the heavier components resist volatilization.5Journal of Loss Prevention in the Process Industries. Experimental analysis of the evaporation process for gasoline – Section: Gasoline weight loss
The total mass of fuel in the container does decrease as evaporation progresses, because material is physically leaving. But what is left behind is not the same gasoline you started with. The vapor pressure drops and the evaporation rate slows as the light fraction disappears, a relationship that follows a predictable pattern based on how much weight has already been lost.6Fire Safety Journal. Changes in evaporation rate and vapor pressure of gasoline with progress of evaporation – Section: Conclusion In practical terms, this means stale gasoline in a sealed container does not lose meaningful weight, but gasoline stored in a vented or poorly sealed container over weeks or months can lose its most volatile fraction, leaving behind a heavier, less combustible residue that may not burn well in an engine. A properly sealed gas can in a cool location loses very little to evaporation.
The Gas Can Itself Matters More Than You Think
If you are comparing fuel weight across different container sizes or trying to figure out what you can safely load into a truck bed, it helps to know the container weights too. A standard red plastic five-gallon gas can weighs about one to two pounds empty. Metal jerry cans, which seal better and are more durable, can weigh eight to ten pounds empty. So a metal jerry can loaded with five gallons of gasoline comes in at close to 40 pounds total, while a plastic one is closer to 32 or 33 pounds. Two full jerry cans in the back of a truck adds roughly 80 pounds. Five of them, for instance stocking up for a generator before a hurricane, adds 200 pounds to your vehicle’s load.
Container design also affects how well the gasoline keeps its weight. Cheap plastic cans with flexible spouts are notorious for allowing small amounts of vapor to escape around the cap, especially in heat. Metal jerry cans with rubber gasket seals hold vapor in more effectively. If minimizing evaporative loss during storage matters to you, such as for seasonal equipment or emergency fuel reserves, the container’s seal quality has more impact than almost any other factor.
Drop-in Biofuels and Future Density Shifts
As refiners experiment with renewable and bio-based gasoline substitutes, the density of what comes out of the pump could shift further. Research into biomass-derived “drop-in” fuels, designed to replace gasoline without engine modifications, has found that their densities tend to be lower than conventional gasoline. In one study, bio-based formulations ranged from about 737 to 757 kg/m³, compared to 793 kg/m³ for the conventional base gasoline they were tested against.7Thermal Science and Engineering Progress. Turning biomass into gasoline biofuel: A sustainable bridge between bio-innovation and clean energy for modern engines – Section: 3.2.4. Fuel density The differences come from the precise mix of hydrocarbons, additives, and oxygenates in each formulation. A lower-density biofuel would mean five gallons weighs slightly less. Whether you would notice the difference at the pump is doubtful, but at scale, even small density changes affect how much energy a tanker truck delivers and how refiners calibrate their blending operations.
For drivers, the practical takeaway is that the weight of five gallons of whatever comes out of the pump is unlikely to change dramatically in the near future. Even the lightest biofuel formulations measured in current research would put five gallons at around 28 to 29 pounds, still firmly in the same ballpark as today’s gasoline. The bigger variable will continue to be ethanol content and seasonal reformulation, not whether the hydrocarbons came from crude oil or corn stalks.
Quick Reference by Container Size
Since people search for the weight of gasoline in specific quantities, here is how the math scales using the middle of the typical range, about 6.1 pounds per gallon:
- 1 gallon: about 6 pounds
- 2.5 gallons: about 15 pounds (common small gas can size)
- 5 gallons: about 30 to 31 pounds
- 10 gallons: about 61 pounds
- 20 gallons: about 122 pounds (a typical sedan’s full tank)
These are fuel weights only. Add one to ten pounds for the container depending on whether it is a thin plastic jug or a heavy metal can. For quick estimation when you do not need precision, rounding to 6 pounds per gallon keeps the arithmetic simple and gets you within a pound or two of the real figure at any quantity.