24 MPG combined might raise an eyebrow, considering the 2019 Mercedes-Benz C300 Convertible is not a hybrid. However, this rating should be understood given *what* this car is: a stylish, open-top cruiser designed to deliver a premium experience. Buyers of a C300 Convertible aren’t seeking Prius-level efficiency; they want comfort, performance, and open-air motoring.

City and highway performance

The EPA estimates translate to 21 MPG in the city and 29 MPG on the highway. This split reflects the engine’s tuning and the nine-speed automatic transmission’s programming. The turbocharged 2.0L four-cylinder produces ample torque, allowing for effortless acceleration around town. The transmission keeps the engine in its best operating range, responding quickly and smoothly to throttle inputs. On the highway, the C300 Convertible settles into a relaxed cruise, using the higher gears to minimize fuel consumption and engine noise. The 29 MPG figure is achievable on long road trips, if you resist the urge to exploit the engine’s responsive nature too frequently.

Annual fuel cost

The EPA calculates the annual fuel cost for the 2019 Mercedes-Benz C300 Convertible at $2,400. This figure is based on driving 15,000 miles per year, with a mix of city and highway driving, using the EPA’s combined MPG rating. It also considers the national average fuel price (for premium fuel, which is recommended for optimal performance). This $2,400 expense should be factored into the overall cost of ownership, but many C300 Convertible buyers consider it a reasonable trade-off for the vehicle’s attributes.

Real-world expectations

While the EPA estimates provide a useful benchmark, real-world fuel economy can vary depending on driving habits, traffic, and terrain. Aggressive acceleration, frequent stop-and-go traffic, and prolonged idling can all negatively impact fuel consumption. However, smooth and steady driving, on highways with minimal traffic, can often yield results that exceed the EPA’s estimates. The type of fuel used can also make a difference.

The C300 Convertible can technically run on regular unleaded, but premium fuel is recommended to unlock the engine’s full potential and maintain optimal efficiency. Many owners report their C300 MPG across all years and find their numbers sit just slightly below the EPA’s estimates overall.

How it compares

Compared to its competitors, the 2019 Mercedes-Benz C300 Convertible’s fuel economy is competitive. The BMW 430i Convertible, for example, achieves a similar 25 MPG combined with its 2.0L turbocharged engine. The Audi A5 Cabriolet, also equipped with a 2.0L turbo, manages around 27 MPG combined. The Audi offers a slight edge in efficiency, but the differences are small and won’t be a deciding factor for most buyers. These cars are chosen for their styling, brand, and driving experience, not simply for their fuel efficiency. For shoppers considering other Mercedes Benz fuel economy data, the C300 falls in the middle of the pack for the brand across their models.

Tips to maximize efficiency

Take advantage of the C300 Convertible’s driving modes. Selecting “Comfort” mode will soften throttle response and encourage earlier upshifts, promoting greater fuel efficiency in everyday driving. “Eco” mode takes this a step further by optimizing various vehicle systems for maximum fuel savings. You can also create a custom “Individual” mode with a more efficient engine mapping alongside a sporty suspension setup.

Maintain proper tire inflation. Underinflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel. Check your tire pressure regularly and inflate them to the recommended levels specified on the door jamb sticker. This is important on a rear-wheel drive convertible, where optimal grip is vital for performance and safety.

Avoid unnecessary weight. Carrying extra cargo in the trunk or passenger compartment adds weight to the vehicle, which reduces fuel efficiency. Remove any unnecessary items from the car to minimize the burden on the engine. Cleaning out the trunk can improve gas milage, especially if you tend to carry heavy items.

Anticipate traffic flow and drive smoothly. Avoid sudden acceleration and hard braking, which waste fuel. Maintain a consistent speed and anticipate traffic conditions ahead to minimize unnecessary stops and starts. This approach, with the car’s smooth-shifting automatic transmission, leads to greater efficiency.

Limit top-down driving at high speeds. Driving with the top down at highway speeds increases aerodynamic drag, leading to a noticeable decline in fuel economy. Consider raising the top on longer highway stretches to improve efficiency.