Mercedes-Benz B-Class reliability, MPG and running costs
Figures updated
The Mercedes-Benz B-Class is a mpv / people carrier. In 2024 MOT tests it scored 106 for reliability (100 is average), ranking 221 of 442, and 27.5% failed first time against a UK average of 28.5%. Its most common MOT failure is coil spring (3.2% of tests).
Ranked 221 of 442 cars in the 2024 MOT Reliability League, and 6 of 20 people carriers
In 2024, 71,636 Mercedes-Benz B-Classes aged 3 to 20 had an MOT and 27.5% failed first time (UK average 28.5%). Taking age and mileage into account, the Mercedes-Benz B-Class is 6% less likely to fail than the average car of the same age and mileage. At the first MOT, at three years old, 8.8% failed (UK 12.7%).
First-time fail rate
27.5%
UK 28.5%
Fail rate at 3 years
8.8%
UK 12.7%
Average miles a year
6,900
Typical age at test: 10 years
Mercedes-Benz B-Class MOT failure rate by age
Most common Mercedes-Benz B-Class MOT faults
- Coil spring: fractured or broken3.2% of tests
- Malfunction indicator lamp: inoperative or indicates a malfunction2.4% of tests
- Linkage ball joint dust cover: ball joint dust cover no longer prevents the ingress of dirt2.1% of tests
- Ball joint: ball joint excessively worn2.1% of tests
- Joints: constant velocity boot split or insecure, no longer prevents the ingress of dirt2.1% of tests
- Registration plate lamp(s): inoperative in the case of a single lamp or all lamps1.9% of tests
What the Mercedes-Benz B-Class fails on
| Area | Tests failing | vs similar cars |
|---|---|---|
| Lights and electrics | 10.2% | About average |
| Suspension | 8.9% | About average |
| Tyres | 7.0% | About average |
| Brakes | 6.3% | About average |
| Visibility | 4.0% | ▼ 13% less often |
| Exhaust and emissions | 3.1% | About average |
| Body and structure | 3.1% | About average |
| Seat belts and airbags | 1.5% | ▲ 1.7× as often |
| Wheels | 0.8% | ▲ 2.1× as often |
| Steering | 0.4% | ▼ 79% less often |
What MPG does the Mercedes-Benz B-Class do?
Official economy for the Mercedes-Benz B-Class ranges from 34.4 to 74.3mpg across the 292 versions listed by the Vehicle Certification Agency (2006–2025). A typical petrol version manages 47.9mpg and a typical diesel 67.3mpg. Expect 10–15% less in real-world driving.
Work out a journey's fuel costHow much is road tax on a Mercedes-Benz B-Class?
Any Mercedes-Benz B-Class first registered from April 2017 pays the standard rate of £200 a year after its first year (2026/27 rates). A Mercedes-Benz B-Class registered between March 2001 and March 2017 is taxed on its CO2: £20 to £410 a year.
Work out tax for a specific carMercedes-Benz B-Class specs and running costs
Official figures for 292 versions sold in the UK between 2006 and 2025.
Fuel types
Diesel, Electric, Petrol, Plug-in hybrid
Official economy
34.4–74.3 mpg
Electric range
124 miles
Efficiency
3.5 mi/kWh
CO2
23–197 g/km
Power
116–224 PS
| Version | Fuel | Economy | CO2 | Car tax | Company car tax |
|---|---|---|---|---|---|
| B-Class MPV B 200 d150 PS · A8 · listed 2025 | Diesel | 55.4 mpg | 133g | £200 | 36% |
| B-Class MPV B 200163 PS · A7 · listed 2025 | Petrol | 47.9 mpg | 134g | £200 | 32% |
| B-Class MPV B 180136 PS · A7 · listed 2023 | Petrol | 47.1 mpg | 136g | £200 | 33% |
| B-Class MPV B 250 e218 PS · A8 · listed 2023 | Plug-in hybrid | 282.5 mpg | 23g | £200 | 10% |
| B Class .5 B 180 d116 PS · A7 · listed 2021 | Diesel | 62.8 mpg | 119g | £200 | – |
| B-Class MPV .5 B 180 d116 PS · A8 · listed 2021 | Diesel | 57.7 mpg | 134g | £200 | – |
| B-Class MPV B 180 d116 PS · A8 · listed 2021 | Diesel | 48.7 mpg | 133g | £200 | – |
| B Class .5 B 200 d150 PS · A8 · listed 2021 | Diesel | 57.7 mpg | 128g | £200 | – |
| B-Class MPV .5 B 200 d150 PS · A8 · listed 2021 | Diesel | 58.9 mpg | 130g | £200 | – |
| B Class .5 B 220 d190 PS · A8 · listed 2021 | Diesel | 57.7 mpg | 129g | £200 | – |
| B-Class MPV .5 B 220 d190 PS · A8 · listed 2021 | Diesel | 57.7 mpg | 132g | £200 | – |
| B-Class MPV B 220 d190 PS · A8 · listed 2021 | Diesel | 49.6 mpg | 132g | £200 | – |
| B Class .5 B 180136 PS · A7 · listed 2021 | Petrol | 47.1 mpg | 137g | £200 | – |
| B-Class MPV .5 B 180136 PS · A7 · listed 2021 | Petrol | 47.9 mpg | 137g | £200 | – |
| B Class .5 B 200163 PS · A7 · listed 2021 | Petrol | 47.1 mpg | 137g | £200 | – |
Economy and CO2 are official WLTP figures. Car tax is the yearly rate at current rates for a car first registered in the year listed, before any expensive car supplement. Company car tax is the 2026/27 benefit-in-kind rate. Showing the 15 most recent of 292 versions.
What a Mercedes-Benz B-Class costs to fuel
- petrol, typical official 47.9mpg…
- diesel, typical official 67.3mpg…
Official figures are usually 10–15% better than real-world driving.
Work out a journey in a Mercedes-Benz B-ClassBuying a used Mercedes-Benz B-Class?
Check the MOT history of the exact car: every result, advisory and mileage reading, free.
Compare the Mercedes-Benz B-Class with other people carriers
Reliability, economy, car tax and running costs side by side.
Other Mercedes-Benz models
Frequently asked questions
›Is the Mercedes-Benz B-Class reliable?
Its MOT record is better than average: the Mercedes-Benz B-Class is 6% less likely to fail than the average car of the same age and mileage, with a reliability score of 106 in our 2024 league (100 is average).
›What are common problems with the Mercedes-Benz B-Class?
The most common MOT fault is “Coil spring: fractured or broken”, found in 3.2% of tests. It fails on seat belts and airbags more often than similar cars.
›What MPG does the Mercedes-Benz B-Class do?
Official economy for the Mercedes-Benz B-Class ranges from 34.4 to 74.3mpg across the 292 versions listed by the Vehicle Certification Agency (2006–2025). A typical petrol version manages 47.9mpg and a typical diesel 67.3mpg. Expect 10–15% less in real-world driving.
›How much is road tax on a Mercedes-Benz B-Class?
Any Mercedes-Benz B-Class first registered from April 2017 pays the standard rate of £200 a year after its first year (2026/27 rates). A Mercedes-Benz B-Class registered between March 2001 and March 2017 is taxed on its CO2: £20 to £410 a year.
›How many Mercedes-Benz B-Classes fail their MOT?
27.5% of Mercedes-Benz B-Classes aged 3 to 20 failed their MOT first time in 2024, and 8.8% failed at their first MOT.
Sources: DVSA anonymised MOT tests 2024, all versions of the Mercedes-Benz B-Class combined (Open Government Licence v3.0); official economy and CO2 from Vehicle Certification Agency data, © Crown copyright. VCA cannot accept liability for its accuracy. How we calculate the league.