Mercedes B-Class — MPG & Fuel Costs 2025
Mercedes' compact family MPV, sharing a platform with the A-Class but offering elevated seating and higher headroom.
TL;DR
42 MPG
Real-world petrol
52 MPG
Real-world diesel
43L
Tank capacity
£58.82
Full tank (petrol)
14.8p
Per mile (petrol)
Real-World Fuel Economy: The Mercedes B-Class achieves an estimated 42 MPG (petrol) and 52 MPG (diesel) in real-world UK driving conditions, accounting for a 12% WLTP real-world penalty.
Forecourt Fuel Cost: Refueling the 43-litre tank completely costs approximately £58.82 (petrol) or £61.10 (diesel) at average UK fuel price rates.
Fuel economy at a glance
42
Real-world MPG
Petrol
49.6
Official WLTP
Petrol
52
Real-world MPG
Diesel
61.4
Official WLTP
Diesel
Annual fuel costs by mileage
| Annual mileage | Petrol | Diesel |
|---|---|---|
| 5,000 miles/yr | £740 | £621 |
| 7,400 miles/yr(UK average) | £1096 | £919 |
| 10,000 miles/yr | £1481 | £1242 |
| 15,000 miles/yr | £2221 | £1863 |
| 20,000 miles/yr | £2961 | £2485 |
| Full tank (43L) | £58.82 | £61.10 |
| Cost per mile | 14.8p | 12.4p |
Based on UK average fuel prices: petrol 136.8p/L · diesel 142.1p/L. Prices updated regularly.
How does the B-Class compare?
Tips to get better MPG from your B-Class
Select Eco mode to keep the gearbox in higher gears for longer, lowering engine RPM.
Upshift early to utilize the turbo engine's low-end pull.
Avoid carrying unnecessary weight in the boot.
Is the cheaper petrol station worth it?
In a Mercedes B-Class achieving ~42 MPG real-world, if you fill 34 litres and the alternative station is 10p/litre cheaper:
£3.40
Gross saving on fuel
£0.44
Cost of 3-mile detour
£2.96
Net saving ✓
You could drive up to 23 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 B-Class?
The Mercedes B-Class achieves approximately 42 MPG in real-world petrol driving — around 12% lower than the official WLTP figure of 49.6 MPG due to real driving conditions. Diesel variants achieve around 52 MPG real-world.
How much does it cost to fill a Mercedes B-Class?
The Mercedes B-Class has a fuel tank of 43 litres. At the UK average of 136.8p/litre for petrol, a full tank costs approximately £58.82. Diesel costs approximately £61.10 for a full tank.
What is the annual fuel cost for a Mercedes B-Class?
At the UK average annual mileage of 7,400 miles and current petrol price of 136.8p/litre, a Mercedes B-Class costs approximately £1096 per year in fuel. At 10,000 miles/year the cost rises to £1481. Actual costs vary with your driving style and mileage.
Is it worth driving to a cheaper petrol station in a Mercedes B-Class?
In a Mercedes B-Class doing ~42 MPG real-world, driving 3 miles round-trip to save 10p/litre on a 34-litre fill nets approximately £2.96 after the extra fuel cost. You could drive up to 23 miles before the saving is eaten up. Use the WorthThePump calculator for your exact situation.
How much does the Mercedes B-Class cost per mile in fuel?
The Mercedes B-Class costs approximately 14.8p per mile in petrol at current UK prices. Over a typical commute of 30 miles per day, that is approximately £4.44 per day in fuel.
What is the WLTP MPG figure for the Mercedes B-Class?
The official WLTP fuel economy figure for the Mercedes B-Class is 49.6 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 B-Class
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