21 MPG combined isn’t going to win any fuel efficiency awards, but in the context of the 2021 Porsche 718 Boxster GTS 4.0, it’s almost beside the point. This isn’t a car bought for its frugality; it’s acquired for its hair-raising performance, its scalpel-sharp handling, and the soul-stirring wail of its naturally aspirated flat-six engine. To expect Prius-like numbers from a car this focused would be to misunderstand its purpose entirely.

City and highway performance

The EPA estimates suggest 19 MPG in the city and 24 MPG on the highway for the 718 Boxster GTS 4.0 equipped with the automatic (PDK) transmission. These figures are a product of the engine’s inherent characteristics. The 4.0-liter flat-six needs to breathe to deliver its exhilarating performance, especially in the upper reaches of the rev range. Frequent stop-and-go traffic in urban environments keeps the engine from reaching its optimal operating efficiency. Conversely, consistent speeds on the highway, while tempting to exceed in a Porsche, allow the engine to settle into a more economical rhythm, resulting in the marginally better highway figure.

Annual fuel cost

The EPA estimates the annual fuel cost for driving the 2021 Porsche 718 Boxster GTS 4.0 at $2,750. This figure is calculated based on driving 15,000 miles per year, assuming current national average fuel prices. Premium fuel is required in this Porsche, which contributes to this higher annual cost. If you plan to pilot your Boxster more aggressively (as is surely the temptation) or rack up even more mileage, expect this number to climb considerably. It’s also worth checking local fuel prices regularly, as state and city taxes can significantly influence how much you pay at the pump.

Real-world expectations

Anyone considering a 718 Boxster GTS 4.0 likely understands that the EPA estimates are just a starting point. Real-world fuel economy will vary widely based on driving style, traffic conditions, and even the types of roads you frequent. Spend most of your time blasting through canyons or carving up backroads, and you’ll likely see figures below the EPA estimates. If you can resist the urge to fully exploit the engine’s capabilities and primarily use the car for longer highway cruises, you might match or even slightly exceed the 24 MPG highway figure. But remember, this car rewards spirited driving, and resisting that temptation can prove genuinely challenging.

How it compares

Compared to other performance-oriented roadsters, the 718 Boxster GTS 4.0’s fuel economy falls roughly in line. A BMW Z4 M40i achieves a combined 25 MPG, a noteworthy advantage, but it lacks the visceral engagement and naturally aspirated charm of the Porsche. The Audi TT RS, even with its turbocharged five-cylinder engine, manages around 22 MPG combined. Move into the realm of slightly larger, more luxurious convertibles, and the Mercedes-AMG C43 Cabriolet nets around 22 MPG as well. Ultimately, the Porsche’s slightly lower MPG is often a trade-off that buyers are willing to make for the Boxster’s unparalleled driving experience and distinct character. To see all Porsche fuel economy data, navigate to the model pages.

Tips to maximize efficiency

While the 718 Boxster GTS 4.0 isn’t designed for maximum fuel economy, there are steps you can take to improve it. Avoid aggressive acceleration and braking. The more smoothly you drive, especially when using the automatic transmission, the better your fuel economy will be.

Optimize tire pressure. Ensuring your tires are properly inflated reduces rolling resistance, which directly impacts fuel consumption. Consult the sticker on the driver’s side doorjamb for the recommended pressure.

Minimize idling. Modern engines consume fuel even when stationary. Turn off the engine if you anticipate idling for more than a minute or two. The engine’s quick restart system makes this convenient.

Consider using the “Normal” driving mode on longer highway drives. While the “Sport” and “Sport Plus” modes sharpen throttle response and shift points, they also encourage more aggressive driving and waste fuel. The “Normal” mode provides a more relaxed, efficient driving experience.

Keep up with routine maintenance. Regular oil changes, air filter replacements, and spark plug maintenance all contribute to optimal engine performance and fuel efficiency. Neglecting these can subtly degrade fuel economy over time. And remember to check 718 MPG across all years to compare Boxster numbers and data.