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How much does aviation fuel weigh? At 15 °C, avgas 100LL weighs about 6.0 lb per US gallon (0.72 kg per litre) and Jet A or Jet A-1 about 6.7 lb per US gallon (0.80 kg per litre). So 100 US gallons of avgas is roughly 600 lb (272 kg), and 100 US gallons of Jet A roughly 670 lb (303 kg). Density changes with temperature and fuel batch, so use the figures in your aircraft flight manual for real loading.
Pilots buy fuel by volume, read it on gauges by volume, and then have to load and balance the aircraft by weight. Getting the conversion wrong can put an aircraft over its maximum takeoff weight or outside its centre-of-gravity limits, and mixing up kilograms and pounds has caused serious incidents. This guide gives the numbers, the method and the common traps.
Convert any quantity with the Aviation Fuel Weight Converter.
Typical fuel densities
| Fuel | kg per litre | lb per US gallon | Typical use |
|---|---|---|---|
| Avgas 100LL | 0.72 | 6.0 | Piston training aircraft (Cessna 152/172, Piper PA-28) |
| Mogas / UL91 | about 0.74 | about 6.2 | Rotax-engined light aircraft where approved |
| Jet A-1 / Jet A | 0.80 (range about 0.775–0.840) | about 6.7 | Turbine aircraft and diesel piston engines |
Values are at 15°C. The figures in your aircraft’s flight manual take priority.
The unit conversions
- 1 US gallon = 3.785 litres
- 1 imperial gallon = 4.546 litres
- 1 kg = 2.2046 lb
- Weight = volume in litres × density in kg/L
Worked examples
Light trainer. A Cessna 172 is loaded with 40 US gallons of Avgas. 40 × 3.785 = 151.4 L; × 0.72 = 109 kg (240 lb). Many training aircraft flight manuals simply use 6 lb per gallon, which gives the same 240 lb.
Turbine aircraft. A fuel order of 2,000 kg of Jet A-1 at 0.80 kg/L needs 2,000 ÷ 0.80 = 2,500 litres. If the fueller’s density on the day is 0.78, the volume needed is 2,564 litres.
Imperial gallons. Some older UK and Commonwealth aircraft gauges show imperial gallons. 30 imperial gallons of Avgas = 136.4 L = 98 kg.
Why density changes
Fuel expands as it warms. On a hot ramp a litre weighs a little less than on a cold morning. For light aircraft the difference is usually small; for larger aircraft operators use the density measured at fuelling. Fuel receipts for jet fuel often show the density, so use it in your load calculations.
Traps to avoid
- kg vs lb. Confirm which unit the fuel order, gauge and load sheet use. A figure in pounds read as kilograms gives less than half the fuel expected.
- US vs imperial gallons. An imperial gallon is 20% bigger.
- Usable vs total fuel. Weight and balance includes unusable fuel in the basic empty weight on many aircraft; planning uses usable fuel. Check the flight manual.
- Wrong fuel type. Jet A-1 in a piston engine designed for Avgas can cause engine failure. Always check fuel grade, colour (100LL is dyed blue) and the filler cap markings, and drain a sample before flight.
Putting it into weight and balance
Once you have the fuel weight, multiply by the fuel tank arm to get its moment, then add it to the loading sheet. The Weight and Balance Calculator and the weight and balance guide walk through the full calculation. Remember that the centre of gravity moves as fuel burns, so check it at landing weight too.
Related tools and guides
- Aviation Fuel Weight Converter
- Aviation Fuel Calculator
- Time, Speed and Distance: E6B Basics
- Student Pilot Ground School Toolkit
For training and general information. Typical densities from ASTM D910, ASTM D1655 and Def Stan 91-091. Use approved aircraft and operator data.
Sources and further reading
- FAA Pilot’s Handbook of Aeronautical Knowledge (FAA-H-8083-25) (fuel systems)
- ASTM D910 (aviation gasoline) and ASTM D1655 (Jet A and Jet A-1) specifications, which set the allowed density ranges
- FAA Aircraft Weight and Balance Handbook (FAA-H-8083-1B, PDF)
Sources checked November 2026. Rules differ between countries and change over time: for real flights, use the current publications of the authority that applies to you, your aircraft flight manual and your operator’s procedures.