Fuel Weight Volume Calculator
Converting between fuel volume (US gallons) and fuel weight (pounds) is a routine step in aircraft weight and balance calculations. The standard FAA values are 6.0 lb/US gal for aviation gasoline (avgas 100LL) and 6.7 lb/US gal for Jet-A turbine fuel. This calculator converts in both directions: gallons to pounds and pounds to gallons, for both fuel types. Select the fuel type, enter either volume or weight, and the calculator returns both the equivalent weight and volume, plus the fuel's weight in kilograms for metric reference.
Fuel weight conversion formula
Weight (lb) = Volume (US gal) x Density (lb/gal)
Volume (US gal) = Weight (lb) / Density (lb/gal)
Weight (kg) = Weight (lb) / 2.20462
The FAA Aircraft Weight and Balance Handbook (FAA-H-8083-1B) uses 6.0 lb/gal for avgas as the standard for weight and balance calculations. Jet-A density of 6.7 lb/gal is the standard planning value. Actual density varies with temperature by approximately 0.003 lb/gal per degree Fahrenheit.
Common fuel quantities reference
- Cessna 172 (standard tanks, avgas): 56 total / 53 usable gallons = 318 lb usable.
- Piper PA-28-181 (avgas): 50 total / 48 usable gallons = 288 lb usable.
- Jet fuel is measured in pounds for airline operations, not gallons, due to density variation at altitude.
- 1 US gallon = 3.78541 liters. 1 Imperial gallon = 1.20095 US gallons.
Fuel weight volume calculator: frequently asked questions
How much does avgas weigh per gallon?
Aviation gasoline (avgas 100LL) weighs approximately 6.0 pounds per US gallon at standard temperature. This is the standard value used in FAA weight and balance calculations for piston-engine aircraft.
How much does Jet-A fuel weigh per gallon?
Jet-A (the standard US turbine fuel) weighs approximately 6.7 pounds per US gallon at standard temperature. The exact value varies with temperature and batch. Some operators use 6.72 or 6.84 lb/gal depending on temperature.
Why does fuel density matter for weight and balance?
Fuel weight is added to the weight and balance calculation as an arm-weight moment pair. Since fuel volume (gallons) is displayed on the fuel gauges and at the fuel pump, converting to pounds is necessary for the weight and balance form. An error here directly affects the calculated CG.
Does temperature affect fuel weight?
Yes. Fuel density decreases with higher temperature. At 59 degrees F (15 degrees C), avgas is approximately 6.01 lb/gal. On a hot summer day (100 degrees F), avgas may be closer to 5.9 lb/gal. For planning, 6.0 lb/gal is the standard conservative value used in most FAA weight and balance documentation.
What is the difference between usable and total fuel?
Total fuel is all fuel in the tanks. Usable fuel is total minus unusable fuel (the quantity that cannot be fed to the engine due to aircraft geometry in all approved attitudes). Only usable fuel counts toward endurance and range. Unusable fuel is still included in the weight and balance calculation as part of the basic empty weight.
Official sources
- FAA Aircraft Weight and Balance Handbook (FAA-H-8083-1B): faa.gov.
- ASTM D1655 Standard Specification for Aviation Turbine Fuels: astm.org.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.