Mercedes-Benz B-Class running costs and reliability

2019 onwards (change model)

Running costs rating: 3.6 out of 53.6

Written by Alan Taylor-Jones Published: 27 July 2023 Updated: 1 August 2023

Miles per pound (mpp) ⓘ

Low figures relate to the least economical version; high to the most economical. Based on WLTP combined fuel economy for versions of this car made since September 2017 only, and typical current fuel or electricity costs.

Petrol engines	5.1 - 6.9 mpp
Diesel engines	6.6 - 7.9 mpp
Plug-in hybrid petrol engines *	6.0 - 6.4 mpp

* Fuel economy of the engine when operating without assistance from the electric motor and battery.

What is miles per pound?

Fuel economy ⓘ

Low figures relate to the least economical version; high to the most economical. Based on WLTP combined fuel economy for versions of this car made since September 2017 only.

Petrol engines	34.5 - 47.1 mpg
Diesel engines	51.4 - 61.4 mpg
Plug-in hybrid petrol engines *	40.9 - 43.5 mpg

* Fuel economy of the engine when operating without assistance from the electric motor and battery.

View mpg & specs for any version

What are the running costs?

Diesel the more frugal option
No plug-in hybrid
Mild hybrid economy boost not huge

On paper the B-Class isn’t as efficient as the BMW 2 Series Active Tourer, although not by much. Officially the petrol should do mid-40s mpg with the diesel better at mid-50s. Drive with restraint on motorways and A roads and you’ll be able to get close in the diesel, with harder driving still returning mpg in the 40s.

View detailed mpg and CO2 figures on our Mercedes B-Class specs pages

Diesel models get a regular stop/start system while the petrol is a mild hybrid. This allows the engine to be turned off for extended periods of time even when the car is moving. It does save a little fuel, but the petrol will still be a thirstier option.

Servicing and warranty

You get a fairly typical three-year warranty with the B-Class, although it is at least for an unlimited mileage. This is similar to BMW but well behind Lexus. You can extend the warranty for one or two years, or have it on a one month rolling contract.

Mercedes offers something called Servicecare that allows you to budget for servicing costs. It wraps up labour and parts with a guaranteed price for four services and can be paid monthly or upfront.

Reliability

Our owner’s reviews haven’t reported any major issues, although creaking interior plastics have been mentioned. However, there have been a number of issues reported on the closely related A-Class which shares engines, infotainment and many other major components.