The 2020 Mercedes-Benz SLC300 achieves 27 MPG combined, which is acceptable but not exceptional. This isn’t a vehicle bought for hyper-miling. It’s a stylish two-seat roadster designed for open-air enjoyment, and its fuel economy reflects that. Buyers accepting these tradeoffs are often more interested in the performance and prestige associated with the Mercedes-Benz brand and less concerned with squeezing every last mile from a gallon.

City and highway performance

The official EPA estimates for the SLC300 are 23 MPG in the city and 32 MPG on the highway. The city figure reflects stop-and-go traffic, where the engine’s responsiveness is more critical than outright efficiency. The 32 MPG highway rating is believable given the 9-speed automatic transmission, allowing the engine to cruise at lower RPMs and maintain reasonable fuel consumption on long drives.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2020 Mercedes-Benz SLC300 at $2,150. This figure is based on driving 15,000 miles per year and using national average fuel prices for premium gasoline, which the SLC300 requires. Keep in mind that this is just an estimate. Your actual fuel costs will vary depending on your driving habits, local fuel prices, and the number of miles you actually drive.

Real-world expectations

While the EPA numbers provide a benchmark, the real-world MPG you experience with your SLC300 will fluctuate. Aggressive driving, frequent acceleration and hard braking, will severely impact fuel economy, especially in the city. Conversely, consistent highway driving at a moderate speed can often yield results that meet or even slightly exceed the EPA’s 32 MPG highway rating. Terrain also plays a role. Hilly areas will naturally decrease fuel efficiency compared to flat stretches of road.

How it compares

Compared to its competitors, the SLC300’s fuel economy is fairly average for the segment. The BMW Z4 sDrive30i, with its 2.0L turbocharged four-cylinder, achieves a similar 28 MPG combined. The Porsche 718 Boxster, while arguably a more performance-focused vehicle, achieves 24 MPG combined with its base 2.0L engine. Even the significantly more powerful Mercedes-AMG SLC43 manages around 23 MPG combined, which shows how much power and performance impact fuel efficiency. For all Mercedes Benz fuel economy data, be sure to check out the full brand listing. If you are curious about SLC300 MPG across all years, you can find past data sets for comparison.

Tips to maximize efficiency

The SLC300’s 9-speed automatic transmission is designed to optimize fuel economy, but it’s not a magic bullet. Use the “Comfort” driving mode for everyday driving, as it prioritizes smooth shifting and lower RPMs. Avoid aggressive acceleration and braking, as these habits significantly reduce fuel efficiency. Anticipate traffic flow and maintain a consistent speed whenever possible to minimize unnecessary fuel consumption.

Proper tire inflation is critical to maximizing fuel economy. Check your tire pressure regularly and inflate your tires to the recommended pressure listed on the driver’s side doorjamb. Under-inflated tires increase rolling resistance, which forces the engine to work harder and burn more fuel. Conversely, over-inflating can negatively affect ride quality, so it’s important to maintain proper inflation.

Regular maintenance is essential for optimal fuel efficiency. Ensure that your SLC300 receives scheduled oil changes, air filter replacements, and spark plug replacements according to the manufacturer’s recommendations. A well-maintained engine runs more efficiently and burns fuel more cleanly.

Minimize aerodynamic drag by removing unnecessary items from the vehicle, such as roof racks or cargo carriers. Drag increases fuel consumption, especially at highway speeds. Remember that this car is made to be driven with the top down, though! A few extra miles per gallon probably pale in comparison to the fun of driving with the top down in the sunshine.

Consider using cruise control on long highway drives. Cruise control maintains a consistent speed, which can help to improve fuel economy compared to manually controlling the throttle. Just be sure to disengage it in heavy traffic or inclement weather.