Mercedes-Benz S320
18 MPG The 1999 Mercedes-Benz S320 is EPA-rated at 18 MPG combined (15 city / 22 highway). Over 15,000 miles a year that is about 833 gallons, $2667 a year in fuel, or $0.178 per mile at $3.20/gal.
Across its full 1994–1999 run it averages 18 MPG, essentially flat across 6 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 | $0.139 | $1389 | $2083 | $2778 |
| $3.00/gal | $0.167 | $1667 | $2500 | $3333 |
| $3.20/gal | $0.178 | $1778 | $2667 | $3556 |
| $3.50/gal | $0.194 | $1944 | $2917 | $3889 |
| $4.00/gal | $0.222 | $2222 | $3333 | $4444 |
| $4.50/gal | $0.250 | $2500 | $3750 | $5000 |
| $5.00/gal | $0.278 | $2778 | $4167 | $5556 |
Every model year
| Year | Combined | City | Highway | EPA fuel cost/yr | CO₂ g/mi | Trims |
|---|---|---|---|---|---|---|
| 1999 | 18 MPG | 15 | 22 | $4300 | 494 | 2 |
| 1998 | 18 MPG | 15 | 22 | $4300 | 494 | 4 |
| 1997 | 18 MPG | 15 | 22 | $4300 | 494 | 2 |
| 1996 | 18 MPG | 15 | 22 | $4300 | 494 | 2 |
| 1995 | 18 MPG | 15 | 22 | $4300 | 494 | 2 |
| 1994 | 18 MPG | 15 | 22 | $4300 | 494 | 1 |
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 149 large cars models tracked here, the Mercedes-Benz S320 ranks 97 on current figures, against a class average of 21.6 MPG.
Closest more-efficient alternatives in the same class: Cadillac DeVille (18.5), BMW 550i Gran Turismo (19), BMW 750i xDrive (19), BMW 750Li (19), BMW 750Li xDrive (19).
Tailpipe CO₂ is rated at 494 grams per mile, which works out to roughly 7.4 tonnes a year at 15,000 miles.
Questions
What MPG does the Mercedes-Benz S320 get?
The 1999 Mercedes-Benz S320 is rated at 18 MPG combined by the EPA — 15 city and 22 highway. Across all 6 model years in the database it averages 18 MPG, ranging from 18 to 18 depending on year and trim.
How much does a Mercedes-Benz S320 cost in fuel per year?
At 18 MPG and 15,000 miles a year, it burns about 833 gallons — roughly $2667 a year with fuel at $3.20 a gallon, or $0.178 per mile. The EPA's own published annual figure for the 1999 model is $4300.
Has the Mercedes-Benz S320 become more efficient over time?
Barely. It sits at 18 MPG today against 18 in 1994 — essentially flat across 6 model years, with efficiency gains offset by weight and power creep.
Is the Mercedes-Benz S320 efficient for its class?
It ranks 97 of 149 in the Large Cars class on current figures, against a class average of 21.6 MPG. That is 3.6 worse 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.