VFR Fuel Reserve Calculator
How It Works
This vfr fuel reserve calculator uses established formulas to provide accurate results.
The basic rule:
- Trip Fuel = Burn Rate x (Distance / Ground Speed)
- Legal VFR Reserve: 30 min day / 45 min night at normal cruise (FAR 91.151)
- Total Required = Trip Fuel + Legal Reserve + Personal Safety Margin
- Fuel Remaining = Tank Capacity - Trip Fuel
Results are estimates. Consult a professional for critical decisions.
Frequently Asked Questions
What are the legal fuel reserve requirements for VFR?
Under FAR 91.151, VFR flights require enough fuel to fly to the first point of intended landing and then fly for 30 minutes at normal cruising speed during the day, or 45 minutes at night. This is a legal minimum — many experienced pilots carry significantly more. For a Cessna 172 burning 10 GPH, that is 5 gallons (day) or 7.5 gallons (night) of reserve fuel. Unlike IFR, VFR does not require fuel to an alternate airport, but planning for diversions is wise.
How much extra fuel should I carry beyond legal minimums?
Most flight instructors and experienced pilots recommend carrying at least 1 hour of total reserve fuel (30-60 minutes beyond the legal minimum). This provides margin for headwinds stronger than forecast, ATC delays, unexpected weather diversions, and difficulty finding the destination airport. Running low on fuel is consistently among the top 10 causes of general aviation accidents. An extra 15-30 minutes of fuel weighs very little relative to the safety it provides.
How do I plan fuel for a long cross-country flight?
For flights approaching your aircraft's range limit: plan fuel stops every 2-3 hours or when you will arrive with less than 1 hour of fuel remaining. Check fuel prices along the route using ForeFlight or AirNav. Consider headwinds at different altitudes — a higher altitude might have stronger headwinds, burning more fuel despite better efficiency. Always have at least 2 alternate airports identified with fuel availability confirmed. Check NOTAMs for fuel availability at planned stops — small airports sometimes run out.
What should I do if I am running low on fuel in flight?
If fuel is becoming a concern: immediately lean the mixture for best economy (reduces burn rate 15-25%), reduce speed to best-endurance speed (lower than best-range speed), identify the nearest suitable airport and divert immediately, declare a fuel emergency (Mayday) with ATC if you have less than 30 minutes of fuel — this gives you priority handling. Do not wait until the situation is critical to declare an emergency. Pilots often delay diverting hoping to make their destination, which turns a manageable situation into a dangerous one.