23 MPG combined is, frankly, beside the point for the 2024 Mercedes-Benz AMG CLA45 S 4matic. Nobody shelling out for a hand-built, 416-horsepower, turbocharged four-cylinder monster is prioritizing fuel sippage. This car isn’t about responsible commuting; it’s a precision instrument designed to carve corners and launch down straights, all while broadcasting a distinct AMG snarl. The fuel economy is a necessary evil, an asterisk on the spec sheet for the buyer who understands performance comes at a price. They are seeking raw performance, track-honed handling and aggressively stylish looks. Those priorities overshadow mundane concerns like maximizing miles per gallon.

City and highway performance

The EPA estimates suggest 20 MPG in the city and 28 MPG on the highway. The city figure reflects the stop-and-go nature of urban driving, where the CLA45 S’s aggressive turbo spools down and the boost is rarely fully deployed. The highway figure is more palatable, but even then, resisting the urge to exploit the engine’s immense power will be a constant challenge. It’s tempting to downshift and unleash the fury, which will, of course, negatively impact that number. The eight-speed AMG Speedshift dual-clutch transmission (AM8) is primarily tuned for lightning-fast shifts, not economical cruising. Expect the transmission to hold lower gears longer, keeping the engine in its powerband at the slightest hint of spirited driving. Essentially, achieving the advertised highway MPG requires restraint that runs contrary to the very spirit of this machine.

Annual fuel cost

The EPA estimates the annual fuel cost for operating the 2024 Mercedes-Benz AMG CLA45 S 4matic at exactly $2,500. This figure is based on driving 15,000 miles per year, using national averages for premium fuel prices. It’s crucial to understand that this is just an estimate. Your actual fuel expenses will depend heavily on your driving habits, traffic conditions, and the ever-fluctuating cost of gasoline. Someone who only uses the car for weekend blasts on twisty backroads will likely spend more, while someone who religiously adheres to speed limits and avoids aggressive acceleration might spend less, but likely not much less. The CLA45 S encourages enthusiastic driving, and that eats fuel.

Real-world expectations

Forget about consistently replicating those EPA numbers in the real world. Expect something lower, particularly if you regularly indulge in the CLA45 S’s performance capabilities. Factors like aggressive acceleration, frequent use of Sport or Race modes, and heavy traffic will all conspire to drag down your MPG. Owners report figures closer to the high teens in mixed driving conditions, especially if they live in urban areas with frequent congestion. Long highway journeys, driven with a light foot, might approach the EPA’s 28 MPG, but that requires a level of self-control few CLA45 S owners can muster. The car is simply too eager, too responsive, too much fun to drive slowly.

How it compares

Compared to its rivals, the AMG CLA45 S lands roughly where you’d expect. The Audi RS3, also packing a potent turbocharged engine and all-wheel drive, reports 23 MPG combined. The BMW M2, with its larger inline-six, is rated at 19 MPG Combined. The Cadillac CT4-V Blackwing is considerably less fuel efficient at 18 MPG combined. A fairer comparison might be to the Mercedes-AMG C43 sedan at 22 MPG combined, which offers similar performance characteristics albeit in a larger vehicle. The slight edge some rivals might have in MPG is unlikely to sway potential AMG CLA45 S buyers. This buyer isn’t cross-shopping based on fuel efficiency. They might briefly glance at the numbers, but the deciding factors are performance, handling, and the undeniable allure of the AMG badge. See all Mercedes Benz fuel economy data for more context. And check out AMG MPG across all years to see the trend over time.

Tips to maximize efficiency

Resist the temptation to bury the throttle at every opportunity. The CLA45 S’s immense power is addictive, but gentle acceleration and anticipating traffic flow can significantly reduce fuel consumption. Treat the accelerator pedal with respect, especially in city driving.

Use the “Comfort” driving mode when cruising. While it won’t transform the CLA45 S into an economy car, it will soften the throttle response and encourage earlier upshifts, which are all factors that will save fuel. Reserve the “Sport” and “Race” modes for those moments when you truly want to unleash the car’s full potential.

Ensure your tires are properly inflated. Underinflated tires increase rolling resistance, which negatively impacts fuel economy. Check your tire pressures regularly and maintain them at the recommended levels as indicated on the doorjamb sticker.

Minimize idling. Letting the engine idle for extended periods wastes fuel. If you’re stopped for more than a minute, turn off the engine, unless the weather conditions require you to keep the climate control running.

Keep up with routine maintenance. A well-maintained engine is a more efficient engine. Regular oil changes, air filter replacements, and spark plug inspections will ensure that your CLA45 S is running at its peak efficiency and that you’re not wasting fuel due to neglected maintenance.