2018 Porsche 911 Turbo S Cabriolet MPG & Specs — Real-World vs EPA, All Trims
Every gas trim of this model takes premium.
Is the 2018 Porsche 911 Turbo S Cabriolet good on gas?
At up to 21 MPG combined, the 2018 Porsche 911 Turbo S Cabriolet is about average for a Minicompact Cars — that class averages about 21.0 MPG across 1,649 EPA-tested versions, so it's middle-of-the-road for its size.
Real-world MPG vs the EPA number
The EPA figures above come from a standardized dynamometer test, not the open road — real-world MPG typically runs a bit lower depending on your driving, climate and terrain. That's true of every car on this site, old or new.
At today's AAA national average price — $4.68/gal for premium gas as of 2026-07-05 — the most efficient trim runs about $3,343/year (roughly $279/month, about $22.29 per 100 miles) at the EPA's assumed 15,000 miles/year, using an estimated 714 gallons a year. We don't estimate a cost-per-fill since exact tank size isn't in the public EPA dataset, but the per-100-mile figure scales to any tank. Current national average gas prices →
2018 Porsche 911 Turbo S Cabriolet trims & fuel economy
| Trim (engine / transmission) | Fuel | MPG | Fuel/yr (today's price) |
|---|---|---|---|
| 3.8L 6-cyl, AM-S7 automatic, AWD | PREMIUM | 21 | $3,343 |
2018 Porsche 911 Turbo S Cabriolet specs
What the EPA test-car listings record for this model year — every combination sold is a row in the trims table above.
| Engine options | 3.8L 6-cyl turbo |
| Transmission | AM-S7 automatic |
| Drive type | AWD |
| EPA body class | Minicompact Cars |
| Fuel | Premium |
| Tailpipe CO₂ | 430 g/mi |
Other years of the Porsche 911 Turbo S Cabriolet
Similar cars (Minicompact Cars)
Cars that take premium · Cheapest cars to fuel · Where fuel grade depends on the trim · Fuel guides
1 trim(s) · EPA FuelEconomy.gov data retrieved 2026-07-24 · fuel prices AAA national average as of 2026-07-05.