Aviation volume conversions
Fuel capacity may be listed in U.S. gallons, liters or occasionally imperial gallons depending on the aircraft, country and documentation. Converting volume correctly is important before calculating fuel weight, endurance or cost.
U.S. gallons and liters
One U.S. gallon equals about 3.785 liters. Ten U.S. gallons is therefore about 37.85 liters. To convert liters back to U.S. gallons, divide by 3.785.
Quarts
One U.S. gallon contains four U.S. quarts. Quarts are more common for oil and servicing quantities than for total fuel capacity, but the same unit discipline applies.
Imperial gallons are different
An imperial gallon is larger than a U.S. gallon. One imperial gallon is about 4.546 liters, or about 1.201 U.S. gallons. Treating the two gallon types as interchangeable can create a serious quantity error.
Volume is not weight
Converting gallons to liters does not tell you fuel weight. Weight depends on fuel density, so after volume is converted you still need the appropriate fuel-density factor if the next calculation uses pounds or kilograms.
Check the source label
A capacity number without a unit is not safe to assume. Verify whether the aircraft documentation says U.S. gal, imp gal or liters before entering the value into a planner.
Usable capacity still matters
Total tank volume may include unusable fuel. When planning endurance, use the approved usable-fuel quantity rather than assuming the entire listed capacity can be consumed in flight.
Related PilotDesk guides
Fuel weight · Fuel planning · Endurance and range