Rankings / Aircraft types / Boeing 777-300ER
2025 fuel burnBoeing 777-300ER
The 777-300ER is the stretched, long-range 777, first delivered to Air France in 2004. It carries more seats per flight than any other type in this table. United and American fly it.
- 2,784gallons per airborne hour
- 62.8seat-miles per gallon
- 329seats per flight on average
- 25,157gallons burned per flight
What the figures say
Boeing 777-300ER ranks 21 of 25 types for seat-miles per gallon in 2025, at 62.8. The Boeing 737-800, the most common type in the table, flew 79.1, so a gallon on the Boeing 777-300ER carried a seat 21% less far. Over 1,000 miles, one seat on this type accounts for about 155 kg of CO2 from the fuel burned.
US airlines burned 494 million gallons on the Boeing 777-300ER in 2025, 2.6% of the fuel burned on all scheduled passenger flying, over 177 thousand airborne hours and 20 thousand departures. The average flight spent 9.0 hours in the air and burned 25,157 gallons.
Since 2014, when it was first flown in volume, the type's figure has risen from 62.1 to 62.8 seat-miles per gallon (1.2%). Its best year was 2018, at 65.0. Fuel per airborne hour rose 5.5%, from 2,638 to 2,784 gallons.
Airlines get different results from the same aircraft. United Airlines flew 66.6 seat-miles per gallon on it and American Airlines 58.1, a gap of 15%. The seat count explains most of it: United Airlines put 350 seats on each flight against 304 at American Airlines. Flight length differs too, at 9.7 hours in the air per flight for United Airlines and 8.4 for American Airlines, and longer flights burn less fuel per seat-mile, which helps United Airlines. What's left comes from taxi and holding time, weight, engines, how each airline operates and how it allocates fuel to types when it reports, and the filings can't separate those.
What one seat costs the climate
CO2 for one seat on a Boeing 777-300ER, from the fuel burned, at the 2025 average.
- 78 kgover 500 miles
- 155 kgover 1,000 miles
- 311 kgover 2,000 miles
Who flies it, and how they burn
Boeing 777-300ER by airline, 2025
| Airline | Fuel (million gallons) | Gallons per airborne hour | Seats per flight | Hours per flight | Seat-miles per gallon |
|---|---|---|---|---|---|
| United Airlines | 272 | 2,808 | 350 | 9.7 | 66.6 |
| American Airlines | 222 | 2,754 | 304 | 8.4 | 58.1 |
Seats on the Boeing 777-300ER, airline by airline
The Boeing 777-300ER has 276 seats at United Airlines and 304 at American Airlines, 10% more on the same model. The seat count is what each airline reports for its own aircraft in 2025, for airlines with 10 or more.
Boeing 777-300ER fleets, 2025
| Airline | Aircraft | Average seats | Fewest to most | Average age |
|---|---|---|---|---|
| United Airlines | 22 | 276.0 | 276 | 7.5 |
| American Airlines | 20 | 304.0 | 304 | 11.3 |
See every airline's fleet on the fleets page.
Similar-sized aircraft
These types carry within about 25 seats of the Boeing 777-300ER, so they compete for the same routes.
How to read this. Fuel is what airlines issued to the type in 2025, as filed with the US Bureau of Transportation Statistics, counted only for the hours spent on scheduled passenger flights and divided by the hours in the air. It includes fuel burned taxiing and holding, so it's higher than the cruise figure in a manual. CO2 is 9.75 kg per gallon of jet fuel.
More from Boeing
Browse the Boeing manufacturer hub and its other profiled types:
- Boeing 737 MAX 9
- Boeing 737 MAX 8
- Boeing 787-10
- Boeing 737-900ER
- Boeing 757-300
- Boeing 737-800
- Boeing 787-9
- Boeing 787-8
- Boeing 737-700
- Boeing 757-200
- Boeing 767-400ER
- Boeing 777-200
- Boeing 767-300ER
Nearby in fuel efficiency
Types on either side of this one in the seat-miles per gallon table, regardless of size:
Aircraft references
Source: US Bureau of Transportation Statistics (BTS), Schedule T-2 fuel and airborne hours; US EPA jet-fuel CO2 factor. See the methodology and flight-hour definitions.
Back to all aircraft types, or see how the airlines compare on the airline pages.