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Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →What is the biggest engine in the world? There is no single defensible answer: the Wärtsilä RT-flex96C is the strongest candidate for largest conventional reciprocating engine, the GE9X is a commercial-aircraft size and thrust benchmark, and rocket engines such as BE-4 and RS-25 lead on thrust, but only during launch operations.
Engine size can mean physical dimensions, total swept displacement, rated mechanical output, aircraft thrust, rocket thrust, or historical importance. This representative list covers marine diesels, industrial power engines, civil turbofans, and launch engines without pretending that 80,080 kW of ship power and 512,300 lbf of rocket thrust are interchangeable.
The order is editorial rather than a strict first-to-fifteenth ranking. Each entry identifies the metric that makes the engine notable and separates verified figures from specifications that require a current manufacturer or archival source.
For readers who want broader aviation-specific background after the comparison, The Jet Engine book is an optional technical reference focused on how jet engines work; it complements the aircraft section but does not replace the marine and rocket sources used here.
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Key takeaways
- According to Wärtsilä in 2006, the 14-cylinder RT-flex96C produced up to 80,080 kW, or 108,920 bhp, making it the best-supported candidate for the largest conventional reciprocating marine engine in this comparison.
- According to GE Aerospace in 2025, the GE9X has a 134-inch, or 3.4-metre, fan; GE Aerospace reported a separate 134,300-lbf demonstrated test result in 2019.
- Boeing’s 2026 reference guide lists 110,100 lbf for the GE90-115B and 115,300 lbf for the GE90-115BL, but those are reference ratings rather than the GE9X’s test result.
- According to NASA’s 2025 RS-25 fact sheet, one RS-25 produces 512,300 lbf of vacuum thrust and 418,000 lbf at sea level, weighs approximately 3,515 kg, and measures approximately 4.3 by 2.4 metres.
- Blue Origin gives the BE-4 two different headline figures: 550,000 lbf for the cited 2025 product configuration and up to 640,000 lbf sea-level capability on the current New Glenn page.
What does largest engine mean?
Largest engine is not a single engineering category. A meaningful comparison must identify whether the measurement is physical size, total swept displacement, continuous shaft power, aircraft thrust, rocket thrust, mass, or historical importance.
| Comparison metric | Best suited to | What the figure measures | Why it cannot rank every engine |
|---|---|---|---|
| Physical scale | Marine engines, turbofans, rocket engines | Length, height, diameter, mass, or installation envelope | A physically larger engine may produce less power or thrust than a smaller, more highly stressed design. |
| Total swept displacement | Reciprocating diesel and gas engines | The combined cylinder volume displaced by pistons | Displacement does not directly state rated output, efficiency, torque, or operating speed. |
| Mechanical output | Marine and industrial engines | Continuous shaft power in kW or bhp | Shaft power depends on rotational speed and is not the same quantity as thrust. |
| Aircraft thrust | Turbofan engines | Forward force, normally reported in lbf or newtons | Rated, demonstrated, takeoff, and maximum figures can describe different operating conditions. |
| Rocket thrust | Launch engines | Propulsive force at sea level or in vacuum | Sea-level and vacuum thrust are different figures, and rocket engines usually operate for a launch burn rather than continuous ship service. |
| Operating regime | All engine types | Continuous marine duty, airline service, or short-duration launch operation | An engine optimized to run continuously cannot be judged by the same criterion as one optimized for maximum launch thrust. |
For that reason, the following is a representative cross-sector set rather than a false ranking from number one through number fifteen. The list includes marine, industrial, aircraft, and rocket engines because each sector has a different definition of size and power.
Which 15 engines belong on a largest-engines list?
| Engine | Type and application | Manufacturer | Headline metric | Why it is notable |
|---|---|---|---|---|
| Wärtsilä RT-flex96C | Low-speed, two-stroke marine reciprocating engine for very large container ships | Wärtsilä | Up to 80,080 kW, or 108,920 bhp, for the 14-cylinder version; Wärtsilä reported this figure in 2006. | The strongest candidate here for the largest conventional reciprocating marine engine. Its design priority is enormous low-speed torque, long-duration operation, and efficient ship propulsion. See Wärtsilä’s 2006 announcement. |
| MAN B&W 11G95ME-C10.5 | Ultra-large, low-speed two-stroke marine engine for large-ship propulsion | MAN Energy Solutions | The model designation indicates an 11-cylinder, approximately 950-mm-bore class; a final installed rating was not verified in the supplied primary-source pass. | A modern ultra-large marine comparison to the RT-flex96C. The model belongs on the list, but the available evidence does not support calling it the absolute world record holder. |
| WinGD X92 | Large-bore, low-speed marine engine family for large ships | WinGD | X92 identifies the large-bore engine family; the exact current rating and configuration were not verified in the supplied primary-source pass. | It represents the competing large-bore marine-engine class. It should be treated as a comparison family, not as an unqualified record claim. |
| Wärtsilä 46F | Medium-speed engine family for marine propulsion and land-based power generation | Wärtsilä | Large cylinder-count and high per-cylinder-output platform; the supplied evidence does not provide one final family-wide rating. | The 46F shows that engine scale can mean flexible, high-output medium-speed power rather than the extreme dimensions of a slow-speed container-ship engine. |
| Wärtsilä 31 | Modern four-stroke diesel, gas, or dual-fuel platform for marine and power-generation use | Wärtsilä | Notable for power density and efficiency; no single rating is assigned here because the family has multiple configurations. | Its engineering importance is high output from a four-stroke platform. It belongs in a broad list because largest can refer to class-leading output or power density, not only external size. |
| mtu Series 4000, especially 20V versions | High-output industrial engine family for marine propulsion, power generation, mining, rail, defense, and submarine systems | Rolls-Royce Power Systems, under the mtu brand | Rolls-Royce documents 8-, 12-, 16-, and 20-cylinder versions covering 720–4,300 kW in its 2021 material. | This is industrial scale outside ocean-going container ships. The Series 4000 demonstrates how a large engine can be defined by a broad family, many cylinders, and demanding off-highway applications. See Rolls-Royce’s 2021 Series 4000 release. |
| GE9X | High-bypass commercial turbofan for large widebody aircraft | GE Aerospace | A 134-inch, or 3.4-metre, fan according to GE Aerospace in 2025; 134,300 lbf was a demonstrated test result reported by GE Aerospace in 2019. | The clearest current commercial-aircraft size and thrust benchmark in the supplied research. The 134,300-lbf number is a test result, not automatically the certified operating rating. See GE Aerospace’s 2019 test-result report. |
| GE90-115B | High-thrust commercial turbofan for the 777 generation | GE Aerospace | Boeing’s 2026 reference guide lists 110,100 lbf for the GE90-115B and 115,300 lbf for the GE90-115BL. | The GE90-115B was the previous high-thrust commercial-aircraft benchmark and remains a major operational widebody engine. Its reference ratings should not be compared directly with the GE9X’s demonstrated test figure without labeling the difference. |
| Rolls-Royce Trent XWB-97 | High-thrust civil turbofan for widebody aircraft | Rolls-Royce | The Trent XWB family is specified at 84,000–97,000 lbf; the XWB-97 is the highest-thrust version. | It is the appropriate non-GE comparison for high-thrust civil turbofans. The useful comparison is thrust, fan architecture, aircraft role, and service history—not an unsupported claim that it is physically the largest. See the Trent XWB technical poster. |
| Pratt & Whitney PW4000-112 | Historically important very-high-thrust widebody turbofan | Pratt & Whitney | The supplied source pass did not verify a current exact rating or dimensional specification. | It is included as a historically significant high-thrust commercial-aircraft comparison, not as a sourced record holder. Exact figures should be checked against a current Pratt & Whitney primary source before being added. |
| NASA RS-25 | Reusable, human-rated cryogenic rocket engine for the Space Shuttle heritage and SLS core stage | NASA program; originally developed for the Space Shuttle engine system | NASA’s 2025 fact sheet gives 512,300 lbf vacuum thrust, 418,000 lbf sea-level thrust, approximately 4.3 by 2.4 metres, and approximately 3,515 kg for the current configuration. | Four RS-25 engines power the SLS core stage. Its importance comes from reusable hydrogen/oxygen propulsion, human-rated reliability, and adaptation from Shuttle operations to SLS. NASA program manager Steve Wofford described it as “the only engine with the thrust, reliability and high performance needed for SLS” in NASA’s 2025 RS-25 article. |
| Blue Origin BE-4 | LNG-fueled, oxygen-rich staged-combustion rocket engine | Blue Origin | Blue Origin’s 2025 product page gives 550,000 lbf for the cited configuration; its current New Glenn page states up to 640,000 lbf sea-level capability. | The two official figures describe different product-page contexts and are not interchangeable. The BE-4 is notable for methane-family fuel, oxygen-rich staged combustion, modern launch use, and reusability. Blue Origin calls it “the most powerful liquefied natural gas (LNG)-fueled oxygen-rich staged combustion engine ever flown” on its BE-4 product page. |
| SpaceX Raptor | Full-flow staged-combustion methane/oxygen rocket-engine family for modern launch vehicles | SpaceX | No stable official thrust specification for a precisely identified Raptor version was verified in the supplied source pass. | The Raptor belongs on a modern large-engine list because its full-flow staged-combustion cycle and methane/oxygen propellant combination are technically significant. A precise thrust number would require a version-specific SpaceX or regulatory source. |
| Rocketdyne F-1 | Historic kerosene/liquid-oxygen rocket engine for the Saturn V first stage | Rocketdyne | Exact thrust, dimensions, and mass were not verified from NASA archival material in the supplied source pass. | The F-1’s importance is its role in lunar-launch propulsion and the enormous first-stage thrust demanded by Saturn V. It should be described as a historic benchmark without importing unverified secondary specifications. |
| RD-170/RD-171 family | Historically significant high-thrust liquid rocket-engine family | Manufacturer not confirmed by the supplied primary-source pass | Exact thrust, mass, dimensions, and flight-variant data were not verified from an accessible current primary datasheet. | The family belongs in the historical rocket comparison, but its individual variants should not be collapsed into one number. The RD-170 and RD-171 names represent a family-level entry requiring version-specific verification. |
What is the largest diesel engine ever built?
If largest diesel engine means the best-supported conventional reciprocating marine engine measured by rated mechanical output, the Wärtsilä RT-flex96C is the answer in this list. Wärtsilä reported up to 80,080 kW, equivalent to 108,920 bhp, for its 14-cylinder version in 2006.
“The 14-cylinder Wärtsilä RT-flex96C engine is also the world’s most powerful engine with an output of 80,080 kW (108,920 bhp).”
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The RT-flex96C is not judged by the same criterion as a jet or rocket engine. The RT-flex96C turns fuel energy into continuous crankshaft power and propeller torque at low speed, allowing a very large container ship to move for long periods. Rocket engines produce thrust directly and are optimized for a launch phase, while turbofans produce thrust for aircraft flight.
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How much horsepower does the biggest ship engine make?
The strongest fully sourced ship-engine figure in this article is 108,920 bhp, or 80,080 kW, for the 14-cylinder Wärtsilä RT-flex96C. That figure is a manufacturer-reported 2006 output claim, not a universal ranking of every marine engine by physical mass, displacement, or current production status.
The supplied evidence does not establish a verified total swept displacement, exact mass, or complete physical envelope for the RT-flex96C. Those figures should not be added merely because the engine is widely described as enormous.
What is the most powerful jet engine?
The most defensible answer depends on whether powerful means demonstrated test thrust or certified operating thrust. The GE9X holds the strongest headline test figure in the supplied research at 134,300 lbf, while the GE90-115B family provides the clearest previous commercial-aircraft rating benchmark.
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1Scan for outdated or missing drivers - takes under a minute2Clear out junk files and repair common Windows errors3Fix the driver behind crashes, sound loss and screen glitchesGE Aerospace reported the GE9X’s 134-inch, or 3.4-metre, fan in 2025 in its production coverage. GE Aerospace had reported the 134,300-lbf result in 2019 as a demonstrated test figure. A test result and a certified service rating are different claims, so the GE9X should not be described without that qualification.
GE Aerospace’s David Joyce, then president and CEO of GE Aviation, described the engine this way: “The GE9X engine incorporates the most advanced technologies that GE Aviation has developed during the last decade and is the culmination of our commercial engine portfolio renewal.” The statement appears in GE Aerospace’s 2019 GE9X report.
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| Commercial turbofan | Published headline figure | What the figure means | Best comparison use |
|---|---|---|---|
| GE9X | 134,300 lbf; 134-inch fan | 134,300 lbf is a 2019 demonstrated test result; the 134-inch fan figure was reported by GE Aerospace in 2025. | Current commercial-aircraft size and demonstrated thrust benchmark. |
| GE90-115B | 110,100 lbf | Boeing’s 2026 reference-guide rating for the GE90-115B. | Previous high-thrust 777-generation commercial benchmark. |
| GE90-115BL | 115,300 lbf | Boeing’s 2026 reference-guide rating for the related -115BL reference configuration. | Higher GE90 reference rating, still not the same type of figure as the GE9X test result. |
| Trent XWB-97 | Up to 97,000 lbf | Highest-thrust member of a family specified by Rolls-Royce at 84,000–97,000 lbf. | Non-GE high-thrust civil turbofan comparison. |
| PW4000-112 | Exact figure not verified here | The supplied research identifies the engine as a historically important high-thrust model but does not provide a verified current rating. | Historical context, not a numerical record claim. |
Which is bigger, the GE90 or GE9X?
On the supplied headline figures, the GE9X has the larger stated fan benchmark and the higher numerical thrust result, but the comparison is not perfectly like-for-like: the GE9X figure is a demonstrated test result, while the GE90 figures are Boeing reference ratings. The supplied research does not provide matching overall length, mass, or installation dimensions for both engines, so it cannot prove which complete engine is physically larger on every axis.
The safe conclusion is that the GE9X is the newer commercial-aircraft size and thrust benchmark in this dossier, while the GE90-115B remains the historically important high-thrust engine that preceded it in the 777 family.
What is the biggest rocket engine?
There is no single biggest rocket engine without choosing a metric and operating condition. Among the current, quantified examples here, Blue Origin states up to 640,000 lbf of sea-level capability for the BE-4 on its current New Glenn page, while NASA gives the RS-25 512,300 lbf in vacuum and 418,000 lbf at sea level.
The BE-4’s 640,000-lbf figure and 550,000-lbf product-page figure refer to different stated configurations or contexts. The RS-25’s vacuum figure is also not directly interchangeable with a sea-level figure. Thrust changes with atmospheric pressure, and engine version, test condition, and rating convention matter.
| Rocket engine | Propellant and cycle | Verified thrust information in this dossier | What makes it significant |
|---|---|---|---|
| BE-4 | LNG or methane-family fuel and liquid oxygen; oxygen-rich staged combustion | 550,000 lbf on Blue Origin’s 2025 BE-4 product page; up to 640,000 lbf sea-level capability on the current New Glenn page. | Modern high-thrust launch propulsion with a stated focus on methane-family fuel and reusability. |
| RS-25 | Liquid hydrogen and liquid oxygen; reusable cryogenic engine heritage | 512,300 lbf vacuum and 418,000 lbf sea-level thrust in NASA’s 2025 fact sheet. | Reusable Shuttle heritage, human-rating, and four-engine SLS core-stage use. See NASA’s RS-25 fact sheet. |
| Raptor | Methane and liquid oxygen; full-flow staged combustion | No exact version-specific official thrust figure was verified in the supplied research. | A modern full-flow staged-combustion engine family whose exact performance depends on the Raptor version. |
| F-1 | Kerosene and liquid oxygen | Exact thrust, mass, and dimensions require verification from NASA archival material. | Historic Saturn V first-stage benchmark and a defining lunar-launch engine. |
| RD-170/RD-171 family | Liquid rocket propulsion family | Exact thrust, mass, dimensions, and flight variant require a verified primary datasheet. | Historically significant high-thrust rocket-engine family that should be compared by specific variant. |
The RS-25 and BE-4 illustrate different priorities. The RS-25 combines cryogenic hydrogen/oxygen propulsion, reuse heritage, and human-rated reliability for SLS. The BE-4 uses an oxygen-rich staged-combustion architecture and LNG or methane-family fuel for modern launch systems. Neither design is simply better because one headline thrust number is higher.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.“The RS-25 is the only engine with the thrust, reliability and high performance needed for SLS.”
PerformanceWindows Errors? Fix Them Before They SpreadDriversCrashes, No Sound, or Screen Glitches?PerformancePC Slower Than It Used to Be?Special offer. See more information about Outbyte and uninstall instructions. Please review EULA and Privacy policy.Steve Wofford, SLS Liquid Engines program manager at NASA’s Marshall Center, NASA, 2025
How does a ship engine compare with a rocket engine?
A ship engine and a rocket engine use different primary measures: a ship engine is normally judged by continuous mechanical shaft power and torque, while a rocket engine is judged by thrust at sea level or in vacuum. Converting one into the other requires additional information such as vehicle speed, propulsive efficiency, gearing, and operating conditions.
| Characteristic | Large marine engine | Commercial turbofan | Rocket engine |
|---|---|---|---|
| Primary output | Crankshaft power in kW or bhp | Forward thrust in lbf or newtons | Thrust in lbf or newtons |
| Typical duty | Long-duration or continuous propulsion and power generation | Repeated airline or aircraft flight cycles | Short launch or ascent operation rather than continuous ship propulsion |
| Useful size question | How much torque and shaft power can the engine sustain? | How much thrust and airflow can the fan system produce? | How much thrust can the engine deliver at a specified pressure and propellant condition? |
| Fuel and architecture examples | Diesel, gas, or dual-fuel reciprocating engine | High-bypass turbofan | Hydrogen/oxygen, methane/oxygen, or kerosene/oxygen staged-combustion engine |
| Best candidate in this list | RT-flex96C for reported marine mechanical output | GE9X for commercial-aircraft fan size and demonstrated thrust | BE-4 or RS-25 depending on the selected thrust condition and design criterion |
Why are some engine specifications intentionally missing?
A precise number is useful only when the number describes a clearly identified engine version and condition. The supplied primary-source pass did not verify a final installed rating for the MAN B&W 11G95ME-C10.5 or WinGD X92, a current exact rating for the PW4000-112, a stable version-specific thrust figure for Raptor, or complete archival specifications for the F-1 and RD-170/RD-171 family.
Leaving those cells qualified is more accurate than copying a secondary figure into a table that otherwise mixes manufacturer ratings, test results, sea-level thrust, vacuum thrust, and family-level specifications. The same caution applies to displacement and mass: the RT-flex96C is strongly supported by its rated output, but this dossier does not verify an exact total swept displacement or mass for it.
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How should the 15 engines be ranked?
Rank the engines only after choosing the axis. RT-flex96C leads this set for reported conventional marine mechanical output; GE9X leads the commercial-aircraft fan-size and demonstrated-thrust discussion; BE-4 and RS-25 dominate different rocket-thrust comparisons; and the F-1 and RD family are included for historical launch significance. A single first-to-fifteenth ranking would hide more than it explains.
Frequently Asked Questions
What is the biggest engine in the world?
There is no universal answer to what is the biggest engine in the world. The Wärtsilä RT-flex96C is the best-supported candidate for the largest conventional reciprocating marine engine, with up to 80,080 kW or 108,920 bhp reported by Wärtsilä in 2006. Rocket engines can produce greater thrust, but thrust and marine shaft power are different measurements.
What is the most powerful jet engine?
The GE9X has the strongest commercial-aircraft headline thrust figure in this comparison: GE Aerospace reported a 134,300-lbf demonstrated test result in 2019 and a 134-inch fan in 2025. The GE90-115B remains the previous high-thrust commercial benchmark, with Boeing listing 110,100 lbf for the -115B and 115,300 lbf for the -115BL in its 2026 reference guide.
How much horsepower does the biggest ship engine make?
The largest ship-engine output in this comparison is 108,920 bhp, or 80,080 kW, for the 14-cylinder Wärtsilä RT-flex96C. The figure is a manufacturer-reported mechanical-output rating, not a measurement of thrust, physical mass, or total displacement.
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What is the biggest rocket engine?
Blue Origin states up to 640,000 lbf of sea-level capability for the BE-4 on its current New Glenn page, while NASA lists 512,300 lbf of vacuum thrust and 418,000 lbf at sea level for the RS-25. The two engines cannot be ranked by those numbers alone because the operating conditions and configurations differ.
How does a ship engine compare with a rocket engine?
A marine engine is normally compared by continuous shaft power and torque, while an aircraft or rocket engine is compared by thrust. A rocket engine may produce enormous thrust for a short launch operation, whereas a marine engine is designed to deliver propulsion power for long-duration service.
The Bottom Line
There is no universal biggest engine in the world. The Wärtsilä RT-flex96C is the best-supported largest conventional reciprocating marine engine in this set at 80,080 kW and 108,920 bhp, the GE9X is the clearest commercial-aircraft size and demonstrated-thrust benchmark, and rocket engines such as the BE-4 and RS-25 must be compared by thrust condition, cycle, mass, operating duration, and mission.
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