2021 Porsche 718 Cayman GTS MPG & Specs — Real-World vs EPA, All Trims
Every gas trim of this model takes premium.
Is the 2021 Porsche 718 Cayman GTS good on gas?
At up to 21 MPG combined, the 2021 Porsche 718 Cayman GTS is better than average for a Two Seaters — that class averages about 19.4 MPG across 2,500 EPA-tested versions, so it's a good pick on fuel 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 →
2021 Porsche 718 Cayman GTS trims & fuel economy
| Trim (engine / transmission) | Fuel | MPG | Fuel/yr (today's price) |
|---|---|---|---|
| 4.0L 6-cyl, AM-S7 automatic, RWD | PREMIUM | 21 | $3,343 |
| 4.0L 6-cyl, 6-spd manual, RWD | PREMIUM | 19 | $3,695 |
2021 Porsche 718 Cayman GTS 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 | 4.0L 6-cyl |
| Transmission | AM-S7 automatic · 6-spd manual |
| Drive type | RWD |
| EPA body class | Two Seaters |
| Fuel | Premium |
| Tailpipe CO₂ | 418–458 g/mi |
Other years of the Porsche 718 Cayman GTS
Similar cars (Two Seaters)
Cars that take premium · Cheapest cars to fuel · Where fuel grade depends on the trim · Fuel guides
2 trim(s) · EPA FuelEconomy.gov data retrieved 2026-07-24 · fuel prices AAA national average as of 2026-07-05.