2018 Kia Optima S MPG & Specs — Real-World vs EPA, All Trims
Every trim takes regular — no premium needed.
Is the 2018 Kia Optima S good on gas?
At up to 26 MPG combined, the 2018 Kia Optima S is better than average for a Large Cars — that class averages about 20.3 MPG across 2,605 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 — $3.80/gal for regular gas as of 2026-07-05 — the most efficient trim runs about $2,192/year (roughly $183/month, about $14.62 per 100 miles) at the EPA's assumed 15,000 miles/year, using an estimated 577 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 Kia Optima S trims & fuel economy
| Trim (engine / transmission) | Fuel | MPG | Fuel/yr (today's price) |
|---|---|---|---|
| 2.4L 4-cyl, S6 automatic, FWD | REGULAR | 26 | $2,192 |
2018 Kia Optima S 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 | 2.4L 4-cyl |
| Transmission | S6 automatic |
| Drive type | FWD |
| EPA body class | Large Cars |
| Fuel | Regular |
| Tailpipe CO₂ | 340 g/mi |
Similar cars (Large 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.