The fuel capacity of a Boeing 777 varies significantly by model. The classic 777-200 and 777-300 hold approximately 117,340 liters. The extended-range 777-200ER and 777-300ER carry much more to facilitate long-haul routes, with the 300ER holding up to 181,280 liters. The ultra-long-range 777-200LR has a capacity of 181,283 liters, often supplemented by auxiliary tanks. In 2026, the newest 777-9 (777X) is estimated to hold between 190,000 and 197,000 liters, allowing it to cover massive distances with high efficiency. To put this in perspective, a full tank on a 777-300ER weighs about 145,000 kg—nearly as much as the empty weight of the aircraft itself.