Porsche 718 Cayman S
21.5 MPG The 2025 Porsche 718 Cayman S is EPA-rated at 21.5 MPG combined (19 city / 24.5 highway). Over 15,000 miles a year that is about 698 gallons, $2233 a year in fuel, or $0.149 per mile at $3.20/gal.
Across its full 2021–2025 run it averages 21.5 MPG, essentially flat across 5 model years.
Running cost at different fuel prices and mileages
The figure everyone actually wants, and the one the EPA does not publish — because it depends on a fuel price no agency will commit to.
| Fuel price | Per mile | 10,000 mi/yr | 15,000 mi/yr | 20,000 mi/yr |
|---|---|---|---|---|
| $2.50/gal | $0.116 | $1163 | $1744 | $2326 |
| $3.00/gal | $0.140 | $1395 | $2093 | $2791 |
| $3.20/gal | $0.149 | $1488 | $2233 | $2977 |
| $3.50/gal | $0.163 | $1628 | $2442 | $3256 |
| $4.00/gal | $0.186 | $1860 | $2791 | $3721 |
| $4.50/gal | $0.209 | $2093 | $3140 | $4186 |
| $5.00/gal | $0.233 | $2326 | $3488 | $4651 |
Every model year
| Year | Combined | City | Highway | EPA fuel cost/yr | CO₂ g/mi | Trims |
|---|---|---|---|---|---|---|
| 2025 | 21.5 MPG | 19 | 24.5 | $3575 | 417 | 2 |
| 2024 | 21.5 MPG | 19 | 24.5 | $3575 | 417 | 2 |
| 2023 | 21.5 MPG | 19 | 24.5 | $3575 | 417 | 2 |
| 2022 | 21.5 MPG | 19 | 24.5 | $3575 | 417 | 2 |
| 2021 | 21.5 MPG | 19 | 24.5 | $3575 | 417 | 2 |
Where a model year offered several engines or drivetrains, the figure is the average across all EPA-tested trims that year — the trim count is shown so you can see how much averaging is involved.
How it compares in its class
Among the 105 two seaters models tracked here, the Porsche 718 Cayman S ranks 35 on current figures, against a class average of 21.4 MPG.
Closest more-efficient alternatives in the same class: Mazda MX-5 Miata (21.8), Alfa Romeo Spider (22), Bertone X1/9 (22), Jaguar F-Type S Convertible (22), Jaguar F-Type S Coupe (22).
Tailpipe CO₂ is rated at 417 grams per mile, which works out to roughly 6.3 tonnes a year at 15,000 miles.
Questions
What MPG does the Porsche 718 Cayman S get?
The 2025 Porsche 718 Cayman S is rated at 21.5 MPG combined by the EPA — 19 city and 24.5 highway. Across all 5 model years in the database it averages 21.5 MPG, ranging from 21 to 22 depending on year and trim.
How much does a Porsche 718 Cayman S cost in fuel per year?
At 21.5 MPG and 15,000 miles a year, it burns about 698 gallons — roughly $2233 a year with fuel at $3.20 a gallon, or $0.149 per mile. The EPA's own published annual figure for the 2025 model is $3575.
Has the Porsche 718 Cayman S become more efficient over time?
Barely. It sits at 21.5 MPG today against 21.5 in 2021 — essentially flat across 5 model years, with efficiency gains offset by weight and power creep.
Is the Porsche 718 Cayman S efficient for its class?
It ranks 35 of 105 in the Two Seaters class on current figures, against a class average of 21.4 MPG. That is 0.1 better than typical for the class.
EPA test figures from fueleconomy.gov. Cost per mile and annual fuel spend are computed at a reference price of $3.20 per gallon — use your own price. Estimates based on official test figures and average fuel prices. Real-world consumption varies with driving style, load, terrain and maintenance.