How do you convert aviation fuel between gallons, litres, pounds and kilograms?

To convert aviation fuel, use fixed factors for like-for-like units: 1 US gallon equals 3.78541 litres, and 1 pound equals 0.453592 kilograms. Converting volume to mass requires the fuel’s density: multiply volume by density for mass, or divide mass by density for volume. Never use one universal gallons-to-pounds factor.

For Aviation & Real-World Flying calculations, we separate volume from mass. Gallons and litres measure volume; pounds and kilograms measure mass. That distinction is central to why aircraft fuel is usually planned by mass.

Aviation fuel conversion factors

Volume-to-volume and mass-to-mass conversions use fixed mathematical factors.

Keep the full factor during the calculation and round only the final result. Repeated rounding can create a noticeable discrepancy when converting a large fuel load through several units.

How do you convert gallons or litres to pounds or kilograms?

Use the density of the specific fuel to convert between volume and mass.

mass = volume × density

volume = mass ÷ density

If density is expressed in kilograms per litre, the main aviation fuel conversion formulas are:

• litres to kg = litres × density
• kg to litres = kg ÷ density
• US gallons to kg = gallons × 3.785411784 × density
• kg to US gallons = kg ÷ density ÷ 3.785411784
• litres to lb = litres × density × 2.20462262
• lb to litres = lb × 0.45359237 ÷ density

These rounded values are useful for quick estimates:

These are planning approximations, not universal constants. The required density depends on the fuel grade, batch and temperature; our guide to jet fuel and avgas differences explains why the same shortcut cannot be used for every aircraft.

1. Identify the gallon type. Confirm whether the source uses US or Imperial gallons.
2. Identify the fuel. Jet A, Jet A-1 and avgas have different densities.
3. Convert the volume unit. Change gallons to litres if your density is stated in kg/L.
4. Apply the density. Multiply volume by density to obtain kilograms.
5. Convert the mass if needed. Multiply kilograms by 2.20462262 for pounds.

Worked example: 500 US gallons of Jet A

With 500 US gallons of Jet A and a stated density of 0.800 kg/L, the fuel quantity is approximately 1,893 litres, 1,514 kilograms or 3,339 pounds.

• 500 × 3.785411784 = 1,892.706 L
• 1,892.706 × 0.800 = 1,514.165 kg
• 1,514.165 × 2.20462262 = 3,338.9 lb

The common 6.7 lb-per-US-gallon shortcut gives 3,350 lb. That small difference comes from using a rounded assumed density rather than the stated 0.800 kg/L value.

Which aviation fuel density should you use?

Use the measured density on the fuel documentation when available; otherwise use the approved planning value specified by the operator, aircraft documentation or fuel supplier.

Fuel volume changes with temperature while its mass remains essentially unchanged. If a density is quoted at 15 °C but the volume is measured at a materially different temperature, precise operational work requires an appropriate temperature correction rather than a simple rounded factor. For real-world loading, our explanation of density-based fuel uplift calculations covers that process.

Are aviation gallons US or Imperial?

Aviation documents may use either US or Imperial gallons, so the unit must be confirmed rather than assumed.

One Imperial gallon equals 4.54609 litres or approximately 1.20095 US gallons. Consequently, 100 US gallons is 378.54 litres, while 100 Imperial gallons is 454.61 litres. Confusing the two produces a discrepancy of roughly 20%, far larger than normal density or rounding differences.

What causes incorrect aviation fuel conversions?

Most incorrect results come from mixing unit systems or using the wrong fuel density.

• Treating one litre as one kilogram: that approximation applies to water, not jet fuel or avgas.
• Using 6.7 lb per gallon for avgas: that shortcut is associated with jet fuel; 100LL is commonly estimated at about 6.0 lb per US gallon.
• Confusing US and Imperial gallons: always inspect the aircraft manual, fuel ticket or loading interface.
• Entering mass into a volume field: verify whether a simulator or loading system expects kg, lb, litres or gallons before entering the number.
• Mixing temperature bases: density at 15 °C should not automatically be applied to an observed volume at another temperature when operational precision is required.
• Confusing total and usable fuel: a correct conversion does not make unusable fuel available for flight planning.

Flight simulators may use a fixed internal density or convert the displayed units automatically. When loading a simulated aircraft, follow our fuel calculation and refuelling method for flight simulators and check the unit label before entering the quantity.