Mercedes-Benz S420
16 MPG The 1999 Mercedes-Benz S420 is EPA-rated at 16 MPG combined (14 city / 20 highway). Over 15,000 miles a year that is about 938 gallons, $3000 a year in fuel, or $0.200 per mile at $3.20/gal.
Across its full 1994–1999 run it averages 15.8 MPG, improving by 1 MPG over 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 | $0.156 | $1563 | $2344 | $3125 |
| $3.00/gal | $0.188 | $1875 | $2813 | $3750 |
| $3.20/gal | $0.200 | $2000 | $3000 | $4000 |
| $3.50/gal | $0.219 | $2188 | $3281 | $4375 |
| $4.00/gal | $0.250 | $2500 | $3750 | $5000 |
| $4.50/gal | $0.281 | $2813 | $4219 | $5625 |
| $5.00/gal | $0.313 | $3125 | $4688 | $6250 |
Every model year
| Year | Combined | City | Highway | EPA fuel cost/yr | CO₂ g/mi | Trims |
|---|---|---|---|---|---|---|
| 1999 | 16 MPG | 14 | 20 | $4800 | 555 | 1 |
| 1998 | 16 MPG | 14 | 20 | $4800 | 555 | 1 |
| 1997 | 16 MPG | 14 | 20 | $4800 | 555 | 1 |
| 1996 | 16 MPG | 14 | 20 | $4800 | 555 | 1 |
| 1995 | 16 MPG | 14 | 19 | $4800 | 555 | 1 |
| 1994 | 15 MPG | 14 | 18 | $5150 | 592 | 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 S420 ranks 124 on current figures, against a class average of 21.6 MPG.
Closest more-efficient alternatives in the same class: Dodge Charger SRT8 (17), Ford Crown Victoria Police (17), Maserati Quattroporte GTS (17), Mercedes-Benz S500 (17), Porsche Panamera GTS ST (17).
Tailpipe CO₂ is rated at 555 grams per mile, which works out to roughly 8.3 tonnes a year at 15,000 miles.
Questions
What MPG does the Mercedes-Benz S420 get?
The 1999 Mercedes-Benz S420 is rated at 16 MPG combined by the EPA — 14 city and 20 highway. Across all 6 model years in the database it averages 15.8 MPG, ranging from 15 to 16 depending on year and trim.
How much does a Mercedes-Benz S420 cost in fuel per year?
At 16 MPG and 15,000 miles a year, it burns about 938 gallons — roughly $3000 a year with fuel at $3.20 a gallon, or $0.200 per mile. The EPA's own published annual figure for the 1999 model is $4800.
Has the Mercedes-Benz S420 become more efficient over time?
Yes. It has gone from 15 MPG in 1994 to 16 in 1999 — an improvement of 1 MPG, or 7% across 6 model years.
Is the Mercedes-Benz S420 efficient for its class?
It ranks 124 of 149 in the Large Cars class on current figures, against a class average of 21.6 MPG. That is 5.6 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.