24 MPG combined won’t win any fuel economy prizes, but it’s what you get with the 2024 BMW 840i Convertible. This isn’t basic transportation; it’s a grand touring car, an expression of style and money. Buyers aren’t focused on maximum efficiency; they want open-air fun and a strong engine sound for weekend trips. For them, 24 MPG is acceptable because performance and luxury are more important than saving gas.

City and highway performance

The EPA estimates the 840i Convertible will achieve 21 MPG in the city and 29 MPG on the highway. The city figure reflects urban driving, where the 3.0-liter turbocharged inline-six engine idles and accelerates more. The 29 MPG highway rating shows the engine’s efficiency when cruising, thanks to the smooth-shifting 8-speed automatic transmission (S8) and optimized gearing. Drivers will find the highway number is easier to achieve than the city number, especially on long drives where the engine maintains optimal speed.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2024 BMW 840i Convertible at $2,400. This is based on driving 15,000 miles per year and using the national average fuel price. Remember that premium fuel is recommended for the best performance of the 840i’s engine, which means you’ll likely pay more per gallon than “average.” More spirited driving will increase the annual fuel cost, while careful driving will decrease it. This $2,400 figure is a starting point for understanding fuel costs, and it shows the importance of searching all Bmw fuel economy data if you’re trying to drive a greener BMW.

Real-world expectations

The EPA provides a standard, but real-world fuel economy will vary based on driving style, traffic, and weather. Expect lower MPG if you frequently use Sport or Sport+ driving modes, which prioritize performance. Hard acceleration and braking will also hurt fuel consumption. Using Eco Pro mode and driving smoothly can help you get closer to the EPA estimates. The 840i Convertible provides a thrilling driving experience, and aggressive driving reduces fuel economy. Also check out the 840I MPG across all years to see if drivers in previous years match the official estimates.

How it compares

Among luxury convertibles, the BMW 840i has middle-of-the-road fuel economy. The Mercedes-Benz SL 55 AMG, with its more powerful V8 engine, achieves a combined MPG of only 16. The Porsche 911 Carrera Cabriolet, depending on the configuration, can achieve figures in the low- to mid-20s for combined MPG. The Lexus LC 500 Convertible comes in around 18 MPG combined. The 840i Convertible offers a good balance of performance and efficiency relative to its competitors. For buyers who want open-air fun but still care about fuel costs, the 840i offers a good compromise.

Tips to maximize efficiency

Use the BMW’s Eco Pro driving mode. This setting adjusts throttle response and transmission behavior to prioritize fuel efficiency. It may slightly reduce the car’s responsiveness, but it can make a difference on long drives, and helps you hold a steady speed on the highway.

Keep proper tire inflation. Underinflated tires increase rolling resistance, which reduces fuel economy. Check your tire pressures regularly and inflate them to the recommended levels on the door jamb sticker. This step can improve your MPG and extend tire life.

Anticipate traffic and avoid unnecessary acceleration and braking. By looking ahead and maintaining a consistent speed, you can minimize fuel waste. Coasting to a stop can also help improve your fuel efficiency, though you always want to be aware of surroundings and safety.

Reduce weight in the vehicle. Extra cargo adds weight, forcing the engine to work harder and consume more fuel. Remove unnecessary items from the trunk and rear seats to lighten the load and improve your MPG.

Premium fuel is recommended. Although you *can* use a lower octane fuel in a pinch, you are costing yourself fuel efficiency and overall performance because the engine’s computer management system will have to reduce timing to compensate.