Aviation Fuel Planning Calculator
Fuel required for a flight — taxi, climb, cruise, alternate and reserve (VFR 30/45 min or IFR 45 min) — from trip distance, ground speed and burn rate, with endurance, fuel weight and the maximum payload left.
How it works
Fuel = taxi + climb + (distance ÷ ground speed × burn) + (alternate distance ÷ GS × burn) + reserve minutes × burn + contingency %; endurance = usable fuel ÷ burn
Fuel exhaustion still causes accidents every year, almost always from optimistic planning rather than mechanical failure. The regulatory minimum is trip fuel plus a reserve — 30 minutes by day and 45 at night for VFR in the US, 45 minutes plus fuel to an alternate under IFR, with similar rules elsewhere — but that is a legal floor, not a target. Careful pilots add taxi and climb fuel (climbing burns 50–100% more than cruise), fuel to a realistic alternate, and a contingency for headwinds and reroutes, then set a personal minimum landing fuel of an hour. Ground speed, not true airspeed, drives the sums, so a headwind that adds 20% to the time adds 20% to the trip fuel. Because fuel is heavy, the final check is always weight and balance.
Worked example
240 nm at 120 knots burning 9.5 gal/h: 19.0 gal of trip fuel, plus 1.5 taxi, 2 climb, 3.2 to a 40 nm alternate, 7.1 for a 45-minute reserve and 1.9 contingency — 34.7 gal, comfortably inside 50 gal usable, landing with about 77 minutes of fuel.
Frequently asked questions
How much does a headwind change things?
Recompute with ground speed: 120 kn TAS into 30 kn is 90 kn, turning a 2-hour trip into 2 h 40 min and adding about 6 gal here — more than the whole reserve.
Should I fill the tanks?
If weight and balance allow, yes — fuel in the tanks is the cheapest insurance. Only leave fuel behind when payload or runway performance demands it.
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Planning estimate for education. Always follow the manufacturer’s manual, official charts and your training; conditions on the water and in the air change quickly.