Fuel Burn & Endurance Calculator
Turn usable fuel and fuel flow into endurance and still-air range — with a reserve check before you launch.
How it works
Endurance = usable fuel ÷ fuel flow · Range = endurance × TAS · Usable range = (endurance − reserve) × TAS
Endurance is simply how long the tanks last at a given burn rate, and range is that time multiplied by true airspeed in still air. The figure that actually matters for planning is range after subtracting the required fuel reserve, because you must land with a legal and safe margin, not with dry tanks. Real range also shrinks with headwinds and climb fuel, so treat this as an optimistic still-air ceiling.
Worked example
With 40 gal usable at 10 gph, endurance is 40 ÷ 10 = 4.0 hr. At 120 kt TAS that is 480 nm still-air. Holding a 45-minute reserve leaves 3.25 hr, or about 390 nm of usable range.
Sources: Fuel economy in aircraft — Wikipedia
Frequently asked questions
Does this account for wind?
No — it gives still-air range using true airspeed. A headwind reduces your groundspeed and therefore the distance you cover on the same fuel, so always plan with groundspeed for a real trip and add margin for the climb, which burns more.
What reserve should I use?
Regulations differ by country and by day/night VFR or IFR, commonly 30 to 45 minutes at normal cruise burn. This tool subtracts whatever reserve you enter so you can see the fuel actually available for the trip.
Is fuel flow constant?
Not exactly. Climb burns more than cruise, and leaning changes the rate. For flight planning, use a conservative cruise fuel flow and add a separate allowance for start, taxi and climb.
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This calculator is for educational purposes. Double-check important results before acting on them.