2015 Mercedes-Benz SL400 MPG & Specs — Real-World vs EPA, All Trims
Every gas trim of this model takes premium.
Is the 2015 Mercedes-Benz SL400 good on gas?
At up to 23 MPG combined, the 2015 Mercedes-Benz SL400 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.
EPA updated its fuel-economy equations again for model year 2017 — mostly affecting hybrids and turbocharged engines — and recalculated 2011-2016 ratings to match, in some cases 1-2 MPG lower. The number above already reflects that update.
At today's AAA national average price — $4.68/gal for premium gas as of 2026-07-05 — the most efficient trim runs about $3,052/year (roughly $254/month, about $20.35 per 100 miles) at the EPA's assumed 15,000 miles/year, using an estimated 652 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 →
2015 Mercedes-Benz SL400 trims & fuel economy
| Trim (engine / transmission) | Fuel | MPG | Fuel/yr (today's price) |
|---|---|---|---|
| 3.0L 6-cyl, Automatic 7-spd, RWD | PREMIUM | 23 | $3,052 |
2015 Mercedes-Benz SL400 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 | 3.0L 6-cyl turbo |
| Transmission | Automatic 7-spd |
| Drive type | RWD |
| EPA body class | Two Seaters |
| Fuel | Premium |
| Tailpipe CO₂ | 393 g/mi |
Other years of the Mercedes-Benz SL400
Similar cars (Two Seaters)
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.