20 MPG combined. That’s the reality for the 2021 Porsche 911 Carrera S Cabriolet. And while it might seem underwhelming compared to hybrid SUVs or electric commuters, it’s largely irrelevant to the person who buys this car. This isn’t transportation; it’s an experience, a statement, a reward for a lifetime of hard work. Someone seeking ultimate fuel efficiency simply won’t be cross-shopping a 911.

City and highway performance

The EPA estimates break down to 18 MPG in the city and 23 MPG on the highway. Consider those numbers optimistic. The 3.0-liter twin-turbocharged flat-six, developing 443 horsepower and 390 lb-ft of torque, is just too tempting. This engine is designed to be revved, the PDK transmission egging you on to chase the redline at every opportunity. So while you can achieve those numbers with a very disciplined right foot, most drivers will likely see figures a few MPG lower, especially in urban environments where stop-and-go traffic negates any fuel-saving technologies. The highway number is more achievable, but again, the temptation to exploit the 911’s prodigious passing power is ever-present.

Annual fuel cost

The EPA calculates the annual fuel cost for the 2021 Porsche 911 Carrera S Cabriolet at approximately $2,900. This figure is based on driving 15,000 miles per year, using a blend of city and highway driving cycles, and factoring in the national average fuel price for premium gasoline, which is required for optimal performance. For many 911 owners, this amount is a relatively small price to pay for the driving experience. But even for high-income owners, monitoring real-world fuel economy numbers can be a fun exercise.

Real-world expectations

Don’t expect to duplicate the EPA numbers in the real world; it rarely happens. Aggressive acceleration, spirited cornering, and the general eagerness this car inspires will all take a toll on your fuel economy. Plan on averaging somewhere between 16 and 21 MPG in mixed driving. If you’re tracking the car regularly, that number will plummet. If you’re embarking on a long highway cruise at a consistent speed, you might see 24 or 25 MPG, but again, resisting the urge to unleash the car’s power is crucial.

How it compares

Compared to other high-performance sports cars, the 911’s fuel economy is generally in line with expectations. A BMW M4 Competition Convertible, for example, achieves an EPA-estimated 16 MPG city and 23 MPG highway. A Chevrolet Corvette Stingray Convertible manages a slightly better 15 city / 27 highway. The crucial difference is *why* this matters. To a Corvette buyer, those extra 3 MPG might be a tangible benefit. To a 911 buyer, it’s almost an irrelevant detail. For those concerned, you can research 911 MPG across all years. It’s more important to consider that a Porsche 718 Boxster S Convertible gets even better fuel economy at 20 city / 26 highway, while offering a very similar driving experience and a lower price point, but slightly less power.

Tips to maximize efficiency

While fuel economy might not be the primary concern for a 911 owner, there are still ways to minimize fuel consumption, if only to extend the range between fill-ups.

Avoid short trips. The engine is its least efficient when cold, so multiple short journeys will dramatically decrease your MPG. Combine errands into a single trip to allow the engine to reach its optimal operating temperature and maximize fuel efficiency.

Use the Normal driving mode in the city. While Sport and Sport Plus unleash the engine’s full potential, they also significantly increase fuel consumption. The Normal mode still offers ample power for everyday driving, while optimizing transmission shift points for efficiency.

Maintain proper tire pressure. Underinflated tires increase rolling resistance, leading to higher fuel consumption. Check your tire pressure regularly and inflate them to the recommended levels, which can be found on the driver’s side doorjamb or in the owner’s manual. Porsche has all Porsche fuel economy data readily accessible, but tires are your responsibility.

Reduce excessive idling. Idling wastes fuel and produces unnecessary emissions. If you’re stopped for more than a minute or two, turn off the engine. Modern cars, including the 911, are designed to restart quickly and efficiently. And, finally, remove unnecessary weight. Excess cargo adds to weight, straining the engine and reducing fuel economy. Remove anything you don’t need from the trunk or passenger compartment.