Mercedes-Benz SLC — MPG & Fuel Costs 2025
Mercedes' premium compact roadster, formerly SLK, offering a folding metal roof, comfortable cruising, and efficient diesel engines.
The Mercedes-Benz SLC is an updated version of the third-generation SLK, introducing a renamed model range and a revised interior.
It is powered by refined petrol and diesel engines. The 2.1-litre diesel in the 250d is particularly famous for returning incredible fuel economy for a roadster.
Real-world fuel economy averages a very respectable 58 MPG for the diesel and 40 MPG for the SLC 200 petrol model.
TL;DR
40 MPG
Real-world petrol
58 MPG
Real-world diesel
60L
Tank capacity
£82.08
Full tank (petrol)
15.5p
Per mile (petrol)
Real-World Fuel Economy: The Mercedes-Benz SLC achieves an estimated 40 MPG (petrol) and 58 MPG (diesel) in real-world UK driving conditions, accounting for a 12% WLTP real-world penalty.
Forecourt Fuel Cost: Refueling the 60-litre tank completely costs approximately £82.08 (petrol) or £85.26 (diesel) at average UK fuel price rates.
Fuel economy at a glance
40
Real-world MPG
Petrol
47.1
Official WLTP
Petrol
58
Real-world MPG
Diesel
70.6
Official WLTP
Diesel
Annual fuel costs by mileage
| Annual mileage | Petrol | Diesel |
|---|---|---|
| 5,000 miles/yr | £777 | £557 |
| 7,400 miles/yr(UK average) | £1151 | £824 |
| 10,000 miles/yr | £1555 | £1114 |
| 15,000 miles/yr | £2332 | £1671 |
| 20,000 miles/yr | £3109 | £2228 |
| Full tank (60L) | £82.08 | £85.26 |
| Cost per mile | 15.5p | 11.1p |
Based on UK average fuel prices: petrol 136.8p/L · diesel 142.1p/L. Prices updated regularly.
How does the SLC compare?
Tips to get better MPG from your SLC
The SLC 250d is exceptionally fuel-efficient; use Eco mode to enable sailing/coasting functions.
Cruising with the roof closed improves aerodynamics and fuel economy at highway speeds.
Upshift early to utilize the engine's low-end pull.
Is the cheaper petrol station worth it?
In a Mercedes-Benz SLC achieving ~40 MPG real-world, if you fill 48 litres and the alternative station is 10p/litre cheaper:
£4.80
Gross saving on fuel
£0.47
Cost of 3-mile detour
£4.33
Net saving ✓
You could drive up to 31 miles round-trip before the saving disappears entirely.
Calculate for your exact situationPopular variants
Frequently asked questions
What is the real-world MPG of the Mercedes-Benz SLC?
The Mercedes-Benz SLC achieves approximately 40 MPG in real-world petrol driving — around 12% lower than the official WLTP figure of 47.1 MPG due to real driving conditions. Diesel variants achieve around 58 MPG real-world.
How much does it cost to fill a Mercedes-Benz SLC?
The Mercedes-Benz SLC has a fuel tank of 60 litres. At the UK average of 136.8p/litre for petrol, a full tank costs approximately £82.08. Diesel costs approximately £85.26 for a full tank.
What is the annual fuel cost for a Mercedes-Benz SLC?
At the UK average annual mileage of 7,400 miles and current petrol price of 136.8p/litre, a Mercedes-Benz SLC costs approximately £1151 per year in fuel. At 10,000 miles/year the cost rises to £1555. Actual costs vary with your driving style and mileage.
Is it worth driving to a cheaper petrol station in a Mercedes-Benz SLC?
In a Mercedes-Benz SLC doing ~40 MPG real-world, driving 3 miles round-trip to save 10p/litre on a 48-litre fill nets approximately £4.33 after the extra fuel cost. You could drive up to 31 miles before the saving is eaten up. Use the WorthThePump calculator for your exact situation.
How much does the Mercedes-Benz SLC cost per mile in fuel?
The Mercedes-Benz SLC costs approximately 15.5p per mile in petrol at current UK prices. Over a typical commute of 30 miles per day, that is approximately £4.65 per day in fuel.
What is the WLTP MPG figure for the Mercedes-Benz SLC?
The official WLTP fuel economy figure for the Mercedes-Benz SLC is 47.1 MPG. However, real-world MPG is typically 10–15% lower than WLTP due to cold starts, air conditioning, motorway speeds, and varying loads. WorthThePump uses a 12% real-world penalty to give a more accurate estimate.
Related guides
Find the cheapest fuel for your SLC
Enter your registration and we'll calculate whether the cheaper station nearby is worth the detour — factoring in your SLC's real-world MPG.
Try WorthThePump — it's free