Fuel Burn Rate Calculator
Turn a fuel burn into every unit at once, see the fuel you need for a flight time, and work out your real average burn, per engine figures and specific range.
Fuel flow from the gauges or the cruise figure in your aircraft's manual.
Off-blocks to on-blocks. The average includes taxi and climb, so it comes out above the cruise burn.
Typical values; use your fuel's actual density. It changes with the batch and the temperature.
Type 2:30 or 2.5 for two and a half hours.
For fuel per seat. Use passengers on board for a real flight.
Uses 3.16 kg of CO2 per kg of jet fuel burned, a commonly used factor, not checked here.
How your fuel burn is worked out
Volume and weight are joined by the density. Fuel needed = burn per hour × hours.
- 1
Volume and weight
2,400 kg/h ÷ 0.800= 3,000 L/h
- 2
Every other unit
= 792.5 USG/h= 659.9 IG/h= 5,291 lb/h
- 3
Fuel for 2 h 30 min
2,400 kg/h × 2.5 h= 6,000 kg
- 4
Per minute
2,400 ÷ 60= 40 kg/min
Read more: the formula, a worked example, typical densities and specific range
Fuel burn (or fuel flow) is how much fuel the engines use in an hour. Jets usually show it by weight, in kg or pounds per hour, and light aircraft by volume, in litres or gallons per hour. Volume and weight are joined by the fuel's density, so you need it whenever you go from one to the other.
The formula
litres per hour = kg per hour ÷ density (kg per litre)
kg per hour = litres per hour × density
lb = kg ÷ 0.45359237 · US gallons = litres ÷ 3.785411784 · imperial gallons = litres ÷ 4.54609
fuel needed = burn per hour × flight time in hours
average burn = (fuel at the start − fuel at the end) ÷ block time in hours
total burn = burn per engine × number of engines
specific range = ground speed ÷ burn per hour (nm per kg, lb or gallon)
fuel per nm = burn per hour ÷ ground speed
fuel per seat per 100 km = burn per hour ÷ (ground speed in km/h) × 100 ÷ seats
Worked example
An airliner burns 2,400 kg an hour of Jet A-1 at a density of 0.800 kg per litre. In litres that is 2,400 ÷ 0.8 = 3,000 L/h. In US gallons it is 3,000 ÷ 3.785411784 = 792.5 US gal/h, in imperial gallons 3,000 ÷ 4.54609 = 659.9 imp gal/h, and in pounds 2,400 ÷ 0.45359237 = 5,291 lb/h. Per minute it is 2,400 ÷ 60 = 40 kg.
A flight of 2 h 30 min (2.5 hours) needs 2,400 × 2.5 = 6,000 kg, which is 7,500 litres or 13,228 lb.
The Advanced example uses the same numbers. If the aircraft left with 9,000 kg and arrived with 3,000 kg after 2 h 30 min of block time, the average burn is (9,000 − 3,000) ÷ 2.5 = 2,400 kg an hour. With 2 engines, each one burns 2,400 ÷ 2 = 1,200 kg an hour. At a ground speed of 450 kt the specific range is 450 ÷ 2,400 = 0.1875 nm per kg, so the aircraft uses 2,400 ÷ 450 = 5.33 kg per nm. 450 kt is 450 × 1.852 = 833.4 km/h, so it burns 2,400 ÷ 833.4 × 100 = 288.0 kg (360.0 litres) per 100 km. Shared between 180 seats that is 360.0 ÷ 180 = 2.00 litres per seat per 100 km. At the commonly used factor of 3.16, burning 6,000 kg of jet fuel gives about 6,000 × 3.16 = 18,960 kg of CO2.
Typical densities
| Fuel | kg per litre | lb per US gal | lb per imp gal |
|---|---|---|---|
| Jet A-1 (typical) | 0.80 | 6.68 | 8.02 |
| Avgas 100LL (typical) | 0.72 | 6.01 | 7.22 |
These are typical values only. Jet fuel is allowed to vary across a range, and every fuel gets lighter per litre as it warms up. The density on your fuel receipt, or the one your operator uses, is the one to trust. The jet fuel converter can correct density for temperature.
Why the average burn is higher than cruise
Fuel used over the block time includes start-up, taxi, take-off and climb, when the engines burn much more than in cruise, and the descent, when they burn much less. On short flights the average comes out well above the cruise fuel flow. Fuel flow also falls during a long flight as the aircraft gets lighter.
Specific range and fuel per seat
Specific range tells you how far one kg (or pound, or gallon) of fuel takes you over the ground, so it already includes the wind. Comparing it at different speeds and levels shows which one is cheapest on fuel. Fuel per seat per 100 km is a plain efficiency figure: divide by the seats you have, or by the passengers really on board, which gives a higher number when the flight isn't full.
For training and planning only. Always use the fuel figures in your aircraft's flight manual or your operator's flight planning, and follow your authority's fuel rules. A real fuel plan adds taxi, contingency, alternate and reserve fuel; the flight fuel planning calculator builds one. Checked 14 October 2026.
Common questions
How do you convert fuel burn from kg per hour to litres per hour?
Divide the kilograms per hour by the fuel's density in kg per litre. At a typical Jet A-1 density of 0.80 kg/L, 2,400 kg/h is 2,400 ÷ 0.80 = 3,000 litres per hour. Going the other way, multiply litres by the density.
How do you convert pounds per hour (pph) to gallons per hour (gph)?
Turn pounds into kilograms (× 0.4536), divide by the density in kg per litre to get litres, then divide by 3.785 to get US gallons. For Jet A-1 at 0.80 kg/L that is about 6.68 lb per US gallon, so 1,000 lb/h is about 150 US gal/h. For avgas at 0.72 kg/L it is about 6.0 lb per US gallon.
How much fuel do I need for a flight?
Multiply the burn per hour by the flight time in hours. At 2,400 kg an hour, a 2 h 30 min flight uses 2,400 × 2.5 = 6,000 kg. That is only the burn for the time you enter: a real fuel plan adds taxi, contingency, alternate and final reserve fuel.
How do I work out my actual fuel burn from a flight?
Take the fuel at the start minus the fuel at the end, and divide by the block time in hours. With 9,000 kg at the start, 3,000 kg at the end and 2 h 30 min of block time, the average burn is 6,000 ÷ 2.5 = 2,400 kg an hour. It includes taxi and climb, so it is higher than the cruise figure.
What is specific range?
Specific range is how far you fly on one unit of fuel: ground speed divided by fuel burn. At 450 kt and 2,400 kg/h it is 450 ÷ 2,400 = 0.1875 nm per kg, or 5.33 kg per nm. Pilots use it to compare speeds and altitudes; a higher specific range means less fuel for the same trip.
What is the density of Jet A-1 and avgas?
Typical values are about 0.80 kg per litre for Jet A-1 and about 0.72 kg per litre for avgas 100LL. The real density changes with the batch and with temperature, so use the figure on your fuel receipt or the density your operator gives you.
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Made by Zulu Calculator, part of AlphaZulu LLC. Formulas are shown in full and rule figures are checked against official sources; see how we build calculators.