Plug-in hybrid · Petrol · registered 2021–2024

Mercedes-Benz C 300 e 4MATIC real-world fuel use

n = 942 cars Avg 24,680 km driven per car EEA data 2024 Smaller sample — indicative
On the road this car uses
7.7×
the fuel of its official figure
Official
0.7
Real world
5.6
0510 L/100 km
Real world: total fuel ÷ total distance across 942 cars (EEA OBFCM data, CC BY 4.0). Official: derived from the average WLTP CO2 of 16.8 g/km.
Real fuel use
5.6 L/100 km
50.4 mpg (UK)
Distance with engine off
34%
all models average 28%
Extra fuel per year
+£1,025
vs official, at 15,000 km and £1.40/L
Real CO2 from fuel
130 g/km
official 17 g/km
Illustrative photo
Illustrative photo, not the Mercedes-Benz C 300 e 4MATIC.

How much is really driven with the engine off

Engine off (electric)33.6%
Battery, engine off 33.6% Battery assisting, engine running 5.6% Battery empty, hybrid mode 60.8%

When not driving on battery alone, this model uses about 8.4 L/100 km. Its official electric range is 102 km. Charge more often and your figure drops towards the official one — try the calculator.

Against similar plug-in hybrids

The closest models by kerb weight in the same data.

ModelOfficial → realReal L/100 kmEngine offCarsGap
Mercedes-Benz C 300 e 4MATIC5.634%9427.7×
Volvo V906.227%13,9005.3×
Volvo S906.723%1,8445.7×
Audi A6 50 TFSI e6.924%1,1005.5×
Audi A6 55 TFSI e7.026%5355.3×
Audi A7 55 TFSI e7.226%2874.4×
Audi A7 50 TFSI e7.324%4455.0×
Compare with Volvo S90Compare with Audi A6 50 TFSI eCompare with Audi A6 55 TFSI e

UK company car tax

Benefit-in-kind tax is based on the official CO2 figure (17 g/km average for this model in the data), not on real-world use. Plug-in hybrids approved to the stricter Euro 6e-bis standard show higher official CO2. Under HMRC's current easement, qualifying cars first registered from 1 January 2025 to 5 April 2028 with official CO2 of 51 g/km or more and at least 1 mile of electric range are treated as 1 g/km for company car tax. Check your own car's emission standard and figures before relying on it.

What the rule change means
General information, not tax advice.

Own one? Send us your real figures

Tell us your average fuel use, how often you charge and your typical trip. Owner reports will appear separately from the official data.

Send my figures

Questions

How much fuel does the Mercedes-Benz C 300 e 4MATIC really use?

Across 942 cars in the EEA 2024 fuel meter data, the Mercedes-Benz C 300 e 4MATIC used 5.6 L/100 km (50.4 mpg UK). Its official figure, derived from WLTP CO2, is about 0.7 L/100 km.

Why is the real figure 7.7× the official one?

The official test assumes a high share of electric driving. In real use these cars covered 34% of their distance with the engine off, so the engine ran far more than the test assumes.

Where does this data come from?

From the on-board fuel consumption meters fitted to every new car in the EU since 2021. The European Environment Agency publishes the readings each year under a CC BY 4.0 licence.

Can I get closer to the official figure?

Yes, by charging before most trips and keeping daily journeys within the electric range of about 102 km (official). Use the calculator to see your own likely figure.

Method: all Mercedes-Benz C 300 e 4MATIC plug-in hybrids in the EEA 2024 OBFCM dataset with at least 1,000 km recorded. Full methodology. Data: European Environment Agency, CC BY 4.0.