How Much Does Avgas Weigh per Gallon?

Published by PilotDeskSources, testing & corrections

For quick planning, pilots often use about six pounds per gallon. The more precise FAA standard value commonly referenced at 59°F is about 6.01 lb/US gal. That is a useful planning number, but it should not be treated as if every gallon of aviation gasoline always weighs exactly the same.

The familiar number is a standard planning weight

The FAA Weight & Balance Handbook lists standard aviation-fuel weights that vary with temperature. A commonly used standard value for aviation gasoline is about 6.01 lb per U.S. gallon at 59°F. That makes mental math easy: 10 gallons is roughly 60 pounds, 20 gallons roughly 120 pounds, and 40 gallons roughly 240 pounds.

For an actual aircraft loading calculation, use the value specified by the aircraft manufacturer, operator, approved loading data or other controlling source when one is provided. Fuel density changes with temperature and fuel formulation, so the exact mass of a measured volume can move slightly from the standard training value.

Quick avgas weight examples

Why pilots care about fuel weight

Fuel is often one of the largest variables in a light-aircraft loading problem. Adding fuel changes total weight and total moment; burning fuel changes both again. Whether the center of gravity moves forward, aft or barely moves depends on where the fuel tanks sit relative to the aircraft datum and loaded CG. That is why a real weight-and-balance problem should use the aircraft’s actual arms, moments and envelope instead of only subtracting six pounds per gallon from the gross weight.

Fuel weight also matters when comparing payload and endurance. Carrying more fuel can reduce the passenger or baggage weight available while still remaining within maximum takeoff weight. On the other hand, removing fuel solely to make a loading problem work can reduce endurance and reserve margin, so the loading decision and the fuel-planning decision should be considered together.

Gallons, pounds and the common six-pound shortcut

For quick estimates, multiplying gallons by six is usually close enough to the 6.01 lb/gal standard value to make a fast reasonableness check. If 37 gallons are aboard, six pounds per gallon gives about 222 pounds; using 6.01 gives about 222.4 pounds. The shortcut is useful because it lets a pilot catch obvious loading mistakes before doing the exact calculation.

Do not confuse avgas with Jet A. Turbine fuel uses a different density and should not be converted with the avgas six-pound shortcut. Use the correct fuel type and the value specified by the aircraft or operator.

Source check

PilotDesk’s standard-value note is based on the FAA Weight & Balance Handbook (FAA-H-8083-1B). The current approved aircraft loading information still controls the actual airplane.