The jet engines on aircraft are always a bit bigger than you’d expect, especially if you have the opportunity to get up close and personal. But which are the biggest in the world, and which aircraft do they power?

While there could be various interpretations of the size of jet engines, such as length, thrust, or some other measurement, we’ve gone for fan diameter as a comparison.

Biggest on a widebody

The biggest jet engine on a commercial widebody today comes from the house of GE. The GE90 was introduced in 1995, making its debut on the Boeing 777 for British Airways. The GE90 powers several variants of the 777 family, including the -300ER, the -200LR and the Freighter.

The GE90 brought with it lightweight and innovative carbon fiber blades, using composites for the first time in engine technology. The carbon fiber is mixed with a toughened epoxy, giving the blade strength, despite being one-third of the weight of titanium.

GE90
The GE90 on the longer-range 777s is the biggest in-service engine. Photo: GE

Two variants of the GE90 were produced – the GE90-94B, which powers the Boeing 777-200 and 777-300, and the GE90-115B, which is used on the longer-range variants such as the -200LR and the -300ER. Out of the two, the -115B is very slightly larger in diameter, by just one inch (2.54 cm).

Winner – Boeing 777-200LR, 777-300ER & 777F at 135 inches (343 cm) diameter

Biggest on a narrowbody

The newest narrowbodies fall into two camps – the CFM LEAP series of engines or the Pratt & Whitney Geared Turbofan (GTF) family. Of the two choices, the one that goes biggest is the P&W GTF, but only specific models. The biggest LEAP engine is the 1A, used on the A320neo family of jets, at 78 inches (198 cm). P&W’s 1100G-JM, also used on the A320neo family of engines, surpasses this at 81 inches (206 cm).

pratt and whitney GTF engine
Photo: Pratt & Whitney

The PW1000G-JM has been powering the A320neo since 2016, and the A321neo since 2017. It remains one of two options available to airlines, so it’s not guaranteed that you’ll be on a P&W-powered neo every time. However, it’s fairly easy to spot if you are.

P&W GTF
The flash of green and the teardrop graphic make the GTF family easy to spot. Photo: Pratt & Whitney

The P&W engines surround their high bypass ratio fan blades with green rub strips. These help reduce friction and excess noise, but also provide a handy visual guide to which engine is powering your flight. All P&W GTF engines have a raindrop symbol on the nose cone, as opposed to the spiral that you’ll see on the LEAP engines.

Winner – Airbus A320neo family at 81 inches (206 cm)

Biggest on a regional jet

The regional jet market is dominated by Embraer, with relative newcomer the Airbus A220 also picking up market share. Both families picked P&W to supply the powerplants for the aircraft, and both sport the largest engines in the marketplace.

Helvetic first E2 flight to LCY
The E2s use the P&W GTF. Photo: Joanna Bailey | Simple Flying

The A220 uses the PW1500G, which has a fan diameter of 73 inches (185 cm). The E195-E2 and the E190-E2 use the PW1900G, which also has a fan diameter of 73 inches (185 cm). The A220 has used the powerplant the longest, since back when it was the Bombardier C-series, and gets a slightly higher maximum thrust of up to 25k, compared to 23k on the E2 jets.

Winner – Airbus A220 and Embraer E2 at 73 inches (185 cm)

Biggest future engine

Anyone with an interest in jet engines will already be aware that there is something much bigger on the horizon. The GE9X is the powerplant for the forthcoming Boeing 777X, and holds the Guinness World Record for the highest recorded thrust. It’s a huge beast, with a massive diameter of 134 inches (340 cm), but it’s not the biggest.

GE9X engine on a parked Boeing 777X.
Photo: GE

The biggest engine in the history of commercial aviation will be the Rolls-Royce UltraFan. Set to be the future engine of the most efficient widebodies, the UltraFan will have an epic diameter of 140 inches (355 cm), surpassing even the great size of the GE9X.

Rolls-Royce UltraFan
The UltraFan will be the world's biggest. Photo: Rolls-Royce

While work on the UltraFan is set to pause for a while, we can expect this incredible engine manufacturer to return to its plans in the future. Eventually, it will build the world’s biggest jet engine… well, until someone else makes one a bit bigger.