23 MPG combined for the 2026 Mercedes-Benz AMG CLA45 S 4MATIC is not merely a number; it’s a mission statement. This figure doesn’t position the CLA45 S as a thrifty commuter, nor does it aim to. Instead, it represents a remarkable engineering achievement: extracting 416 horsepower from a 2.0-liter four-cylinder engine while still offering a combined economy that allows for genuinely usable daily driving. The individual who buys this car prioritizes an almost absurd power-to-weight ratio, scalpel-precise handling, and the visceral thrill of an engine that revs with the aggression of a much larger unit. They’re not looking to win any hypermiling contests, but they certainly appreciate that Mercedes-AMG has managed to imbue such a potent machine with an efficiency rating that doesn’t demand constant trips to the pump. This is a car for the driver who wants their track day weapon to also effortlessly navigate their morning commute, without the guilt of single-digit fuel economy.

City and highway performance

Looking closer at the EPA ratings, the 2026 AMG CLA45 S 4MATIC achieves 20 MPG in the city and 28 MPG on the highway. That 20 MPG city figure is particularly telling. It demonstrates a turbocharged engine with electric motor management system and an intelligent 8-speed automatic transmission (AM8) that can temper the beast when confined to urban sprawl. Stop-and-go traffic, the bane of high-performance engines, is managed with surprising compliance, thanks in part to technologies like cylinder deactivation and a swift automatic stop/start system that operates almost imperceptibly. However, let’s be clear: achieving that 20 MPG requires a restrained right foot. The immediate torque delivery and lightning-quick shifts of the AM8 transmission are constantly inviting enthusiastic acceleration, and indulging in that invitation will naturally see the fuel economy figures dip. On the highway, the 28 MPG is genuinely impressive for a vehicle with its performance capabilities. At cruising speeds, the 2.0L 4-cyl settles into a relaxed rhythm, using its advanced aerodynamics and efficient top gears to stretch every gallon. This allows for enjoyable long-distance drives without needing to plan fuel stops with obsessive precision, displaying its dual-nature as both a track toy and a grand tourer.

Annual fuel cost

The EPA estimates an annual fuel cost of $2,500 for the 2026 Mercedes-Benz AMG CLA45 S 4MATIC. This figure is calculated based on driving 15,000 miles per year, with about 45% of that mileage in city driving and 55% on the highway, and using national average fuel prices, which for a high-performance vehicle like this typically means premium unleaded. For the buyer of an AMG CLA45 S, this $2,500 annual cost is often seen as a minor line item in the broader ownership experience. They understand that the price of admission for this level of performance, luxury, and advanced engineering extends beyond the purchase price. The enjoyment derived from 416 horsepower and a 0-60 mph sprint in just over 4 seconds easily justifies this expenditure. It’s the cost of feeding a finely tuned, highly strung performance machine, and it’s a cost they are more than willing to bear for the daily dose of adrenaline and driving satisfaction.

Real-world expectations

In real-world driving conditions, the 2026 AMG CLA45 S 4MATIC will reflect its driver’s intent. If you consistently drive in Sport+ mode, exploit every available gap in traffic, and regularly test the limits of its astonishing grip, expect to see figures closer to the lower end of the EPA city estimate, potentially even dipping into the high teens. The engine, with its twin-scroll turbocharger and sophisticated direct injection, is designed to deliver maximum performance on demand, and that performance consumes fuel. However, for those who use the CLA45 S as a daily driver, employing its Comfort or Individual modes for calmer commuting, the combined 23 MPG is quite attainable. The vehicle’s advanced powertrain management, including a coasting function and efficient turbos, works diligently in the background to conserve fuel when not under duress. The beauty of this car’s fuel economy is its variability; it directly mirrors how you choose to engage with its significant capabilities. It is a car that rewards a disciplined driver with impressive efficiency, but it will equally and enthusiastically burn fuel when provoked.

How it compares

Comparing the AMG CLA45 S 4MATIC’s fuel economy requires looking at its direct rivals in the compact performance sedan segment. Consider the Audi RS3, for instance, which is typically rated around 22 MPG combined (19 City / 28 Highway). While a seemingly minor difference, the CLA45 S maintains a slight edge in overall efficiency while boasting even higher horsepower figures from its 4-cylinder compared to the RS3’s charismatic 5-cylinder. The BMW M240i xDrive Coupe, another close competitor though with a different body style, often achieves around 25 MPG combined thanks to its B58 inline-six engine (23 City / 32 Highway). Here, the M240i subtly outmaneuvers the CLA45 S in highway efficiency, but it doesn’t match the pure, unadulterated aggression or the highly tuned, record-setting 4-cylinder engine of the AMG. The CLA45 S buyer isn’t cross-shopping a Prius; they’re comparing top-tier performance machines where every horsepower and every tenths of a second matters, and in that context, its 23 MPG combined is not just competitive but truly impressive given its performance metrics. For more information on AMG MPG across all years, our database has extensive figures. Similarly, you can explore all Mercedes Benz fuel economy data to understand their broader commitment to efficiency.

Tips to maximize efficiency

Maintaining consistent throttle input and avoiding aggressive acceleration and braking are the simplest ways to improve fuel economy in the CLA45 S. Use the “Comfort” drive mode for daily driving, as it optimizes transmission shift points and engine mapping for efficiency and smooth delivery, rather than outright performance.

Regularly check and maintain proper tire pressures. Underinflated tires increase rolling resistance, forcing the powerful 2.0L engine to work harder than necessary for the same amount of forward motion, directly impacting fuel consumption.

Engage the vehicle’s “gliding” or coasting function when appropriate, typically found in Comfort or Eco drive modes. This momentarily decouples the engine from the transmission when lifting off the accelerator, allowing the car to coast longer and preserve momentum without engine braking.

Avoid carrying unnecessary weight in the trunk or cabin. Even though the CLA45 S is a high-performance machine, excess weight requires more energy to accelerate, leading to higher fuel consumption over time.

Plan your routes to avoid heavy traffic and excessive idling. The 2.0L 4-cyl engine, while efficient for its power, still consumes fuel when stationary, diminishing your overall city MPG.