Fuel Burn Calculator
Estimate total fuel required for a flight including enroute fuel, taxi, climb, reserves, and contingency. Supports US gallons, Imperial gallons, liters, pounds, and kilograms. Choose by distance or by time.
Why This Matters to Pilots
Fuel exhaustion remains one of the leading causes of general aviation accidents. Proper fuel planning with adequate reserves is essential for every flight.
VFR day flights require a minimum of 30 minutes reserve fuel; VFR night requires 45 minutes. IFR flights require fuel to the destination, then to the alternate, plus 45 minutes at normal cruise. Always plan conservatively.
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Frequently Asked Questions
This calculator is for educational and planning purposes only. Always refer to your aircraft's POH/AFM, current NOTAMs, and official weather briefings. No calculator is a substitute for pilot-in-command judgment or CFI guidance. Read our full Safety Disclaimer.
Last reviewed: July 2026
Fuel Burn Planning in Depth
Fuel burn is the rate at which your engine consumes fuel, and it is the foundation on which every range, endurance, and reserve calculation is built. A pilot who knows a realistic burn rate can convert any planned flight time into a required fuel load, and any available fuel into a maximum flight time. Because the engine does not care about your schedule, getting this number right is the difference between arriving with a comfortable reserve and arriving with a problem.
The burn rate you plan with should come from your own aircraft flight manual at the specific power setting and altitude you intend to fly, adjusted upward for real-world conditions. Book figures assume a properly leaned engine, standard atmosphere, and no unusual demands, so most careful pilots plan with a slightly higher burn than the chart shows. This calculator lets you turn that honest burn rate into the fuel and time figures you actually need.
Step-by-Step: How the Calculation Works
The core relationship is simple: fuel required equals burn rate multiplied by time. If you burn 9 gallons per hour and plan a 2.5-hour leg, you need 22.5 gallons for the leg itself. The discipline lies in what you add to that number: taxi and runup fuel, a climb allowance because engines burn more at climb power, and the regulatory reserve appropriate to the flight.
To work in the other direction, divide usable fuel by burn rate to find endurance. Forty-eight gallons usable at 9 gallons per hour yields about 5.3 hours of engine running time before the tanks are dry — from which you must subtract reserves and taxi fuel to find how much is actually available for the trip. The calculator handles both directions so you can plan by time or by fuel.
More Worked Examples
Example 1 — Fuel for a planned leg
A 300-nautical-mile leg at 120 knots groundspeed takes 2.5 hours. At a planned 10 gallons per hour that is 25 gallons for the leg. Add roughly 1.5 gallons for taxi and climb and a 45-minute night VFR reserve of about 7.5 gallons, and the minimum fuel to load is near 34 gallons — comfortably within a 50-gallon usable capacity.
Example 2 — Time available from fuel on board
You have 30 gallons usable and burn 8.5 gallons per hour. That is about 3.5 hours of total running time. Reserving 45 minutes (roughly 6.4 gallons) leaves about 23.6 gallons, or 2.8 hours, for the trip itself. If the planned leg is longer than that, a fuel stop is required rather than optional.
Pilot Decision-Making Context
The number this calculator produces is only as trustworthy as the burn rate you feed it, so the safe practice is to plan conservatively and verify in flight. Note fuel state at top of climb and at each checkpoint, compare actual burn against plan, and treat any adverse trend as a reason to reconsider your destination or stop early. Fuel exhaustion and starvation remain preventable causes of accidents precisely because they yield to disciplined planning.
Fuel burn also interacts with performance trade-offs. A higher cruise power setting shortens flight time but raises the hourly burn, while leaning correctly and cruising at an economical setting stretches range. Running the numbers both ways lets you choose intelligently between speed and endurance for the flight in front of you.
More Questions Answered
Should I plan with the book burn rate or a higher number?
Plan with a realistic rate at or slightly above the book figure for your power setting and altitude. Book numbers assume ideal leaning and standard conditions, so a small margin protects you against real-world variation.
Does the reserve count as usable trip fuel?
No. Reserve fuel is set aside to remain in the tanks on landing. Only fuel above taxi, climb allowance, and reserve should be counted as available for the trip itself.
How do I convert between gallons and pounds of fuel?
Aviation gasoline weighs about 6 pounds per gallon. Multiply gallons by 6 to estimate weight for weight-and-balance work, and remember that burning fuel shifts both weight and center of gravity over the flight.
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