2004 Mercedes-Benz SLK230: MPG and fuel economy
The 2004 Mercedes-Benz SLK230 is rated by the U.S. Environmental Protection Agency at 22 combined MPG, with 19 MPG in the city and 26 MPG on the highway. That puts it well above the average for cars in the Two Seaters class in the same model year.
This page collects every fuel-economy figure the EPA publishes for the 2004 Mercedes-Benz SLK230. Below you will find the headline combined, city, and highway MPG, the estimated annual fuel cost at three different driving levels, the tailpipe CO₂ emissions, and a full breakdown of the engine and drivetrain. The EPA rates 2 separate variants of this car (different engine, transmission, or drivetrain combinations), and you can compare them side by side in the trims table.
Key takeaways
- Returns 21% better combined MPG than the average car in the Two Seaters class for the 2004 model year (18.2 MPG class average).
- The most efficient car in the Two Seaters class for the 2004 model year is the Honda Insight at 47 MPG.
- EPA estimates this car costs around $5,000 more in fuel over five years than an average new vehicle of the same model year.
- Requires premium gasoline, which typically adds about 40 to 60 cents per gallon to the EPA's annual fuel cost estimate.
Fuel economy at a glance
These are the EPA's official ratings for the 2004 Mercedes-Benz SLK230. The numbers come from a standardised laboratory test cycle and are the same figures that appear on the window sticker of every new car. Real-world mileage varies with driving style, weather, fuel quality, and how heavily loaded the car is.
When the EPA tests several variants of the same nameplate (for example, a front-wheel-drive version and an all-wheel-drive version), each gets its own rating. The figures shown here are the headline variant, taken as the configuration with the best combined MPG. The trims table further down covers all 2 variants side by side.
Combined MPG is a 55/45 weighted blend of the city and highway test cycles. The EPA uses it as the single number you can compare across the entire dataset, including hybrids and EVs (which use the equivalent MPGe figure).
| Combined MPG | 22 MPG |
| City MPG | 19 MPG |
| Highway MPG | 26 MPG |
| Annual fuel cost | $3,150 |
| Tailpipe CO₂ | 404 g/mi |
| Fuel type | Premium |
How the 2004 Mercedes-Benz SLK230 compares
The 2004 Mercedes-Benz SLK230 returns 22 combined MPG. Cars in the Two Seaters class for the same model year average 18.2 MPG, which puts this car ahead of the class average by about 21%.
The most efficient car in the Two Seaters class for the 2004 model year is the Honda Insight at 47 MPG. The bar chart below puts the Mercedes-Benz SLK230 alongside the class best and the class average so you can see the full picture.
For broader context, the average new car of the 2004 model year (across all classes) returns 18.4 MPG. Larger vehicles pull the all-cars average down, so do not use that figure on its own to judge a small car or a hybrid. The full list of the most efficient cars of the 2004 model year is on its own page.
Trim variants rated for 2004
The EPA rates 2 separate variants of the 2004 Mercedes-Benz SLK230. The differences come from the engine size, transmission type, and drivetrain (front-wheel drive, all-wheel drive, and so on). The same nameplate can land several MPG apart depending on the configuration you actually buy.
| Engine and transmission | Drive | Combined | City | Highway | Annual cost |
|---|---|---|---|---|---|
| 2.3L, 4-cyl, supercharged, Automatic 5-spd | Rear-Wheel Drive | 22 MPG | 19 MPG | 26 MPG | $3,150 |
| 2.3L, 4-cyl, supercharged, Manual 6-spd | Rear-Wheel Drive | 21 MPG | 19 MPG | 26 MPG | $3,300 |
Annual fuel cost across driving patterns
The headline annual fuel cost the EPA publishes assumes 15,000 miles of driving per year and a fuel mix of 55% city and 45% highway. The dollar figure is calculated using the EPA's current reference price for premium gasoline, which is $4.61/gallon. EPA updates that reference periodically rather than tracking live pump prices, so treat it as a window-sticker estimate rather than today's pump number.
The table below scales the EPA's number to three common driving patterns. The combined MPG and the reference fuel price stay constant, only the annual mileage changes. To get a current-prices estimate, take your local gas price and multiply by 681.8 gallons (the car's annual consumption at the rated MPG).
| Driving pattern | Estimated annual fuel cost |
|---|---|
| Light driver, 7,500 miles per year | $1,575 |
| Average driver, 15,000 miles per year | $3,150 |
| Heavy driver, 25,000 miles per year | $5,250 |
Compare against other Two Seaters for 2004
If you are cross-shopping the 2004 Mercedes-Benz SLK230, the most useful comparison is against the other cars in the Two Seaters class for the same model year. The list below shows the highest-MPG peers, ranked from most to least efficient. Click any of them to open its full page.
The Honda Insight leads this group at 52 MPG, 30 MPG ahead of the 2004 Mercedes-Benz SLK230.
Specifications
The 2004 Mercedes-Benz SLK230 runs a 2.3-liter 4-cylinder supercharged engine paired with a automatic 5-spd, sending power through rear-wheel drive.
Engine, transmission, and drivetrain together drive most of the variation in fuel economy across trims. A larger engine moves the car with less effort but burns more fuel. A turbo lets a small engine punch above its weight, often without much MPG penalty. All-wheel drive adds traction and weight, and usually costs a couple of MPG compared with two-wheel drive of the same engine.
- Vehicle class
- Two Seaters
- Engine
- 2.3L 4-cylinder supercharged
- Transmission
- Automatic 5-spd
- Drivetrain
- Rear-Wheel Drive
- Fuel type
- Premium
- Annual petroleum use
- 13.5 barrels per year
Common questions about the 2004 Mercedes-Benz SLK230
Quick answers to the questions people most often search for when looking up the 2004 Mercedes-Benz SLK230.
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Is the 2004 Mercedes-Benz SLK230 fuel efficient?
Yes. The 2004 Mercedes-Benz SLK230 returns 22 combined MPG, which beats the average car in the Two Seaters class for the same model year by about 21%. -
What MPG does the 2004 Mercedes-Benz SLK230 get?
The EPA rates the 2004 Mercedes-Benz SLK230 at 22 combined MPG, 19 MPG in city driving, and 26 MPG on the highway. Real-world numbers depend on your driving style, the weather, and how loaded the car is. -
How much does it cost to fuel a 2004 Mercedes-Benz SLK230 per year?
The EPA estimates an annual fuel cost of $3,150 for the 2004 Mercedes-Benz SLK230. That figure assumes 15,000 miles of driving per year, a 55% city and 45% highway split, and the EPA's published average fuel price for the rated fuel grade. -
Does the 2004 Mercedes-Benz SLK230 require premium gas?
Yes. The EPA lists the 2004 Mercedes-Benz SLK230 as requiring premium gasoline. Running it on regular can reduce performance and may affect engine warranties, so it is not a recommended way to save at the pump. -
How much CO₂ does the 2004 Mercedes-Benz SLK230 emit?
Tailpipe CO₂ emissions are 404 g/mi. Multiplied across a typical year of driving (15,000 miles) that works out to about 6,059 kilograms of CO₂. -
What is the difference between the city and highway MPG of the 2004 Mercedes-Benz SLK230?
City driving returns 19 MPG and highway driving returns 26 MPG, a gap of 7 MPG. A spread that wide is typical of cars with conventional automatic or manual transmissions, where stop-start city traffic eats more fuel than a steady highway cruise. -
What engine is in the 2004 Mercedes-Benz SLK230?
The 2004 Mercedes-Benz SLK230 has a 2.3-liter 4-cylinder supercharged engine. -
What transmission and drivetrain does the 2004 Mercedes-Benz SLK230 have?
The 2004 Mercedes-Benz SLK230 comes with a automatic 5-spd transmission and rear-wheel drive. -
How does the 2004 Mercedes-Benz SLK230 compare to the best car in its class?
The most efficient car in the Two Seaters class for the 2004 model year is the Honda Insight at 47 combined MPG. The Mercedes-Benz SLK230 returns 22 MPG, a gap of 25 MPG. If you are comparing on fuel economy alone, the class leader is worth a look. -
How much more does the 2004 Mercedes-Benz SLK230 cost in fuel compared to an average car?
The EPA estimates that over five years, the 2004 Mercedes-Benz SLK230 will cost about $5,000 more in fuel than an average new vehicle of the same model year. The difference accumulates because the car uses more fuel per mile, not because of any one-off charge at the dealership.
Source: U.S. EPA fuel economy dataset. Annual fuel cost figures assume 15,000 miles of driving per year and a 55% city, 45% highway split. Real-world mileage varies with driving conditions, vehicle maintenance, fuel quality, and driver behaviour.