Calculate total trip fuel burn, mandatory IFR reserves, and required uplift for flights in pounds (lb), kilograms (kg), or US gallons.
How This Calculator Works
Fuel planning in civil and commercial aviation is strictly regulated by international airworthiness standards (such as FAA 14 CFR Part 121 and EASA Part-CAT). Running low on fuel in an aircraft is a dire emergency, as you cannot pull over to the side of the road.
Total fuel loaded on an aircraft is divided into distinct regulatory categories:
- Taxi Fuel: Fuel burned by the APU and engines during pushback and taxi to the departure runway.
- Trip Fuel: Fuel required to climb, cruise, descend, and execute an approach to the destination.
- Contingency Fuel: Typically 3% to 5% of trip fuel to cover unforeseen routing changes or weather deviations.
- Alternate Fuel: Fuel required to execute a missed approach, climb, fly to the designated alternate airport, and land.
- Final Reserve Fuel: Mandatory 30 to 45 minutes of holding fuel at 1,500 feet above the alternate airport under standard conditions.
Mathematical Formula
Worked Examples
Example 1: Airbus A320 Flight (kg)
Burn rate 2,400 kg/h, flight time 2.5 hours, with 45-minute mandatory reserve.
Trip = 2,400 × 2.5 = 6,000 kg Reserve = 2,400 × (45/60) = 1,800 kg Total = 7,800 kg
Example 2: Cessna 172 Avgas Consumption (US Gallons)
Burn rate 9.0 gal/h 100LL avgas, 3-hour cross-country flight, 45-min VFR reserve.
Trip = 9.0 × 3 = 27.0 gal Reserve = 9.0 × 0.75 = 6.75 gal Total = 33.75 US gallons
Frequently Asked Questions
Why do commercial airlines measure fuel in weight (kg/lb) instead of volume (gallons/liters)?
Jet fuel expands and contracts with ambient temperature. A gallon of fuel in cold winter temperatures contains more mass and energy than a gallon in summer heat. Measuring by weight (mass) guarantees accurate engine energy calculations.
What is the density of Jet A-1 fuel?
Standard Jet A-1 fuel has a nominal density of approximately 0.80 kg per liter (or roughly 6.7 pounds per US gallon) at 15°C.
What happens if an aircraft reaches minimum fuel?
If estimated fuel on landing drops below mandatory final reserve fuel, the flight crew is legally obligated to declare "MAYDAY MAYDAY MAYDAY FUEL" to receive immediate priority landing clearance.
How much fuel does a Boeing 777 or 787 burn per hour?
A Boeing 787-9 burns approximately 5,000 to 5,500 kg (11,000 to 12,000 lbs) of jet fuel per hour during long-haul cruise.
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