Mercedes B-class
Reliability, running costs, and MOT data across 16 years from 117,828 real MOT tests.
Avg Pass Rate
81%
Total Tests
117,828
Best Year
2020 (98%)
Years Covered
16
About the Mercedes B-class
The Mercedes B-class has been tested 117,828 times in 2026 MOT data across 16 model years (2005 to 2020), with an average pass rate of 81%. That's close to the national average of 82%. Available as diesel and electric and petrol.
Best and Worst Years
The 2020 model is the most reliable with a 98% pass rate from 47 tests. The 2008 model has the lowest at 71%. With a 27 point spread, choosing the right year makes a big difference to reliability.
Reliability Trend
Newer MERCEDES B-CLASSs show better MOT pass rates than older ones, with an average improvement of 14 percentage points.
Mileage Across Years
The oldest model in our data (2005) averages 105,799 miles, while the newest (2020) averages 23,364 miles. Older models have covered serious mileage, so suspension and drivetrain wear are worth checking.
Compared to the Mercedes brand average of 87%, the B-class is 6 points lower, placing it among the less reliable Mercedes models.
Estimated Running Costs
Based on 7,400 miles/year, current fuel prices, and MOT pass rate data. Insurance not included.
Full 2020 detailsHow reliable is the Mercedes B-class?
Mercedes B-class by Year
Click any year to see detailed running costs, reliability data, and comparisons with similar cars.
| Year | Pass Rate | Tests | Avg Mileage | |
|---|---|---|---|---|
| 2020 | 98% | 47 | 23,364 mi | |
| 2019 | 93% | 912 | 29,781 mi | |
| 2018 | 90% | 6,729 | 39,021 mi | |
| 2017 | 88% | 9,693 | 48,392 mi | |
| 2016 | 87% | 9,657 | 55,381 mi | |
| 2015 | 86% | 9,871 | 64,066 mi | |
| 2014 | 83% | 15,382 | 72,344 mi | |
| 2013 | 82% | 13,421 | 78,118 mi | |
| 2012 | 81% | 11,092 | 83,827 mi | |
| 2011 | 73% | 6,779 | 84,302 mi | |
| 2010 | 74% | 8,819 | 90,612 mi | |
| 2009 | 74% | 8,277 | 95,335 mi | |
| 2008 | 71% | 6,925 | 100,673 mi | |
| 2007 | 72% | 5,184 | 101,539 mi | |
| 2006 | 71% | 4,235 | 103,535 mi | |
| 2005 | 73% | 805 | 105,799 mi |
Mercedes B-class Guides & Articles
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