The 2015 Mercedes-Benz CLS400 gets 24 MPG combined. While this isn’t record-breaking, it’s important to consider the car’s purpose. This is a stylish four-door coupe with a potent twin-turbo V6 and plenty of luxury, not just a basic car. Buyers often want design and driving experience over pure efficiency, and the CLS400 delivers both.

City and highway performance

The EPA estimates the 2015 CLS400 at 20 MPG in the city and 29 MPG on the highway. This difference shows how the engine can save fuel when cruising at a constant speed. Expect lower MPG on short trips with lots of stopping and starting, but you might reach or exceed 29 MPG on long highway drives. To maximize fuel economy, especially on long trips, carefully use cruise control and drive with a light foot.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2015 Mercedes-Benz CLS400 at $2,400. This is calculated assuming 15,000 miles of driving per year, a mix of city and highway roads, and the average national fuel price. Your actual fuel costs could be different based on your driving style, location, and gas prices. This number assumes the correct fuel type. Premium fuel is recommended to achieve peak performance in the CLS400.

Real-world expectations

EPA figures are a good starting point, but real-world MPG can vary. Owners often report slightly lower numbers in mixed driving, usually between 21 and 23 MPG. Fuel economy will suffer from aggressive driving, frequent short trips, and long periods of idling. However, careful driving and mostly highway miles can push your MPG closer to, or even above, the EPA estimates. Checking the CLS400 MPG across all years can show trends in owner-submitted data.

How it compares

The CLS400’s fuel economy is average for a luxury four-door coupe. The BMW 640i Gran Coupe, which uses a turbocharged inline-six, has similar performance and gets around 24 MPG combined. The Audi A7 3.0T is another competitor that gets about 24 MPG combined, too. The Porsche Panamera offers more powerful engines, but its fuel economy is usually lower, especially for the higher-performance models. The hybrid Panamera models offer significantly better fuel economy if that’s a high priority, but they cost more. Buyers pick the CLS400 because it uniquely combines style, performance, and luxury, accepting the fuel economy as part of that mix. Compare all Mercedes Benz fuel economy data across the entire model range to see where the CLS400 sits.

Tips to maximize efficiency

The CLS400’s ECO mode can help you save fuel. This mode changes the engine settings, throttle response, and transmission shift points for better efficiency. It might make the car feel a little less responsive, but it can improve your overall fuel economy, especially in the city.

Keep your tires properly inflated. If your tires don’t have enough air, they create more resistance, which means the engine has to work harder and use more gas. Check your tire pressure regularly and fill them to the levels listed on the sticker in the doorjamb. Keeping an eye on your tire pressure can save you gas over time.

Watch traffic and avoid speeding up and slowing down quickly. The CLS400’s twin-turbo V6 makes it easy to go fast, but speeding up fast uses a lot more gas than gradually increasing your speed. Also, braking hard wastes energy. Try to plan your routes and drives to avoid sudden bursts of speed.

Remove extra weight from your car. More weight makes the engine work harder and lowers fuel efficiency. Take out anything you don’t regularly need from the trunk and cabin. This simple step can help you get slightly better gas mileage.