Accurately determine the total weight of fuel or gas based on its volume. Essential for logistics, aviation, and transport planning. Supports Gasoline, Diesel, Propane, and more.
Gasoline (Petrol) – 6.073 lb/gal
Diesel Fuel – 7.0 lb/gal
Propane (Liquid) – 4.24 lb/gal
Water (Pure) – 8.34 lb/gal
Avgas (100LL) – 6.01 lb/gal
Jet A (Kerosene) – 6.7 lb/gal
Crude Oil – 7.2 lb/gal
Custom Density
Select the substance to use its standard density.
Enter the specific density of the fluid in kg/L.
Please enter a valid positive density.
Enter the total volume.
Volume must be a positive number.
US Gallons
Liters
Imperial Gallons
Cubic Feet
Cubic Meters
Select the unit of measurement for volume.
Total Calculated Weight
0 lbs
Weight in Metric:0 kg
Volume (Standardized):0 Liters
Density Used:0 kg/L
Formula: Weight = Volume × Density
Weight Comparison (lbs)
Comparing your input volume against Water and Diesel.
What is "Calculate Weight of Gas by Volume"?
When we discuss "calculate weight of gas by volume," we are typically referring to converting a known volume of liquid fuel—such as gasoline (petrol), diesel, or liquid propane—into its corresponding mass or weight. This calculation is critical because fluids are bought and stored by volume (gallons or liters) but often limited by weight (pounds or kilograms) during transport.
While the term "gas" can refer to the gaseous state of matter (like natural gas), in the context of logistics, automotive, and aviation industries, it usually serves as shorthand for gasoline. Understanding the weight of gas is essential for truck drivers managing load limits, pilots calculating takeoff weight, and engineers designing storage tanks.
Who should use this calculator?
Fleet Managers: To estimate haulage weight for fuel tankers.
Pilots: To ensure aircraft remain within safe Center of Gravity (CG) and weight limits.
Boat Owners: To understand how a full tank affects vessel buoyancy and trim.
RVers: To calculate the added weight of fuel and propane for towing safety.
Calculate Weight of Gas by Volume Formula
The core physics behind this calculation is the relationship between mass, density, and volume. The formula is straightforward but requires consistent units.
Weight ($W$) = Volume ($V$) × Density ($D$)
Since density varies by substance and temperature, standard averages are often used for estimation. For example, US Gasoline has an average density of roughly 6.073 pounds per gallon at 60°F.
Variable Breakdown
Variable
Meaning
Common Unit (US)
Common Unit (Metric)
Volume ($V$)
Amount of space the fuel occupies
Gallons (gal)
Liters (L)
Density ($D$)
Mass per unit of volume
lb/gal
kg/L
Weight ($W$)
The force exerted by gravity on the mass
Pounds (lbs)
Kilograms (kg)
Practical Examples
Example 1: Road Trip Planning
Imagine you are driving a large RV with an 80-gallon fuel tank. You want to know how much weight a full tank of regular gasoline adds to your vehicle payload.
Input Volume: 80 Gallons
Substance: Gasoline (approx. 6.1 lb/gal)
Calculation: 80 × 6.1 = 488 lbs
Result: Filling the tank adds roughly 488 pounds to your RV.
Example 2: Propane Tank Refill
You have a standard 500-gallon propane tank for home heating. Propane is lighter than water and gasoline. You need to know the weight of the liquid propane when the tank is 80% full (safe fill limit).
Input Volume: 400 Gallons (80% of 500)
Substance: Liquid Propane (approx. 4.24 lb/gal)
Calculation: 400 × 4.24 = 1,696 lbs
Result: The liquid propane alone weighs 1,696 pounds.
How to Use This Calculator
Select Fuel Type: Choose the substance you are measuring (e.g., Gasoline, Diesel, Jet A). This sets the standard density automatically.
Enter Volume: Input the numerical amount of fluid (e.g., 50, 100).
Choose Unit: Select the unit of measurement for your input (Gallons, Liters, Cubic Feet, etc.).
Review Results: The calculator instantly displays the total weight in both Imperial (lbs) and Metric (kg) units.
Analyze the Chart: Use the dynamic bar chart to see how your selected fuel compares in weight to water and diesel.
Key Factors That Affect Gas Weight Results
While the formula is simple, real-world variables can alter the exact weight of gas by volume.
1. Temperature (Thermal Expansion)
Liquids expand as they get hotter and contract when they cool. A gallon of hot gasoline contains less mass (and therefore weighs less) than a gallon of cold gasoline. This is why fuel is often dispensed volume-corrected to 60°F (15°C) in wholesale markets.
2. Specific Gravity Variations
Not all gasoline is identical. The blend of hydrocarbons (ethanol content, octane rating, seasonal blends) changes the density slightly. Winter blends are often lighter than summer blends.
3. Atmospheric Pressure
While liquids are generally incompressible, if you are measuring gaseous fuels (like natural gas in a gaseous state), pressure is the single biggest factor. Higher pressure compresses more gas into the same volume, increasing weight significantly.
4. Purity and Additives
Diesel fuel often contains additives for cleaning or anti-gelling. These additives have different densities than pure diesel, slightly altering the final weight per gallon.
5. Water Contamination
Water is significantly heavier than fuel (approx. 8.34 lb/gal vs 6.1 lb/gal for gas). If a fuel tank has water contamination at the bottom, the total weight of the liquid volume will be higher than calculated for pure fuel.
6. Measurement Standards (US vs Imperial)
A common mistake is confusing US Gallons with Imperial Gallons. An Imperial Gallon is roughly 20% larger than a US Gallon. Ensure you know which "gallon" your tank capacity uses to avoid massive calculation errors.
Frequently Asked Questions (FAQ)
Does temperature affect the weight of gasoline?
Yes. As temperature rises, gasoline expands, meaning one gallon of hot gas weighs slightly less than one gallon of cold gas. However, the total mass in a closed tank remains the same; only the volume fluctuates.
How much does 1 gallon of gas weigh?
On average, one US gallon of regular gasoline weighs approximately 6.073 pounds (approx. 2.75 kg). Diesel is heavier, weighing about 7.0 pounds per gallon.
Is diesel heavier than gasoline?
Yes, diesel is denser and heavier than gasoline. This higher density is part of why diesel fuel contains more energy per gallon than gasoline.
Why do pilots calculate fuel weight instead of volume?
Aircraft performance (lift, range, balance) depends on weight (mass), not volume. A jet tank holding 1,000 gallons will have a different weight on a hot day versus a cold day, so pilots calculate mass to ensure safety.
What is the density of Liquid Propane?
Liquid propane is relatively light, with a density of about 4.24 pounds per gallon at 60°F. It is significantly lighter than water and gasoline.
How do I convert liters of petrol to kg?
To convert liters of petrol to kilograms, multiply the volume in liters by the density (approx. 0.74 kg/L). For example, 50 liters × 0.74 = 37 kg.
Does the octane rating change the weight?
Slightly. Higher octane fuels often contain different aromatic hydrocarbons which can be denser, but for general estimation purposes, the weight difference is negligible (less than 1-2%).
What is Specific Gravity in this context?
Specific Gravity is the ratio of a fuel's density to the density of water. Since water is 1.0, gasoline (approx 0.74) floats on water because its specific gravity is less than 1.