Mercedes B-Class (2018)

Estimated running costs and MOT pass rates from 6,729 MOT tests in 2024.

Annual Cost

£1,853

£154/month

MOT Pass Rate

90%

Excellent

Road Tax

£200

Standard rate/year

Est. Insurance

Grp 12-25

1595cc Petrol

Great Choice

90% pass rate, £1,853/year to run. 8 points above average.

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Petrol1595cc8 years old6,729 tests39k miles avg

Annual Running Costs

Fuel (Petrol, 1595cc)

~42 mpg

£1,398

Road Tax

Standard rate (from April 2017)

£200

MOT Test

£55

Predicted Repairs

Low estimate due to excellent reliability

£200

Total per year£1,853

Per month£154/mo

Per week£36/wk

Estimates based on 7,400 miles/year (UK average), petrol at 174.57p a litre (GOV.UK weekly average, week of 19 October 2026), GOV.UK road tax rates and repair likelihood from MOT data. Insurance not included. Cars registered from April 2017 pay the £200 standard rate, plus £440 a year for five years (from the second year) if they cost over £40,000 new (over £50,000 for electric cars).

Reliability Verdict

90% MOT pass rate(Excellent)

0%All-model avg: 82%100%

Excellent reliability. Very few MOT failures. That's 8 points above the average of 82% across all models in our data.

90% of MOT tests on Mercedes B-Classs from 2018 ended in a pass in 2024, when they were about 6 years old. That's based on 6,729 tests across the UK, retests included. The average mileage recorded at those tests was 39,021 miles.

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How Does It Compare?

Rank among 2018 models312th of 607(bottom half)

Rank among Mercedes models614th of 1,376(top half)

vs average of all models+8%(82% avg)

vs 2018 models average+1%(89% avg)

vs Mercedes average+3%(87% avg)

Mileage Analysis

39,021

Average miles

44,400

Expected for age

The average 2018 Mercedes B-Class had 39,021 miles on the clock at its 2024 MOT, which is in line with the expected 44,400 miles for a 6-year-old car, suggesting normal everyday use.

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Best Year to Buy?

Of the years with at least 100 tests, the 2019 model has the highest MOT pass rate at 93%, while the 2006 model has the lowest at 71%. The 2018 scores 90%. Newer cars usually pass more often simply because they are younger, so compare years of a similar age.

Mercedes B-Class by Year

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

Similar Cars to Consider

Vauxhall Corsa

2016 · 1398cc Petrol

£2,003/year

81%

-9%

Ford Focus

2016 · 1596cc Petrol

£2,078/year

87%

-3%

Nissan Qashqai

2017 · 1200cc Petrol

£1,780/year

86%

-4%

Volkswagen Polo

2016 · 1198cc Petrol

£1,750/year

84%

-6%

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About the 2018 Mercedes B-Class

The 2018 Mercedes B-Class is a premium car. Our records list a 1595cc petrol engine, though engines vary between versions. 6,729 MOT tests were recorded on this model in 2024, making it a reasonably common sight on UK roads. Among all models from 2018, the average MOT pass rate is 89%, and this model beats that benchmark.

With an average of 39,021 miles recorded at its 2024 MOT tests, Mercedes B-Class owners drive about as much as the UK average.

2018 Mercedes B-Class Fuel Costs

The 1595cc petrol engine offers a reasonable balance between performance and economy. Expect around 42 mpg in mixed driving, which works out to roughly £1,398 per year with petrol at 174.57p per litre (GOV.UK weekly average, week of 19 October 2026; based on 7,400 miles per year).

What does it cost to own a 2018 Mercedes B-Class?

Total estimated annual running cost is £1,853 (£154/month), broken down as £1,398 fuel, £200 road tax, £55 MOT, and £200 predicted repairs. The low repair estimate reflects the excellent 90% pass rate. These cars rarely fail their MOT, so unexpected bills are less likely.

Mercedes B-Class Reliability Trend

Newer Mercedes B-Classs pass their MOT more often than older ones, by 14 percentage points on average, which is mostly down to age and wear.

Buying a Used 2018 Mercedes B-Class

At 8 years old, this is a solid used buy if you find one with good service history. Depreciation has levelled off, so you won't lose much more value. Focus on condition over mileage. If you're flexible on year, the 2019 model has the highest pass rate at 93%. With 6,729 MOT tests in our data, there's strong statistical confidence in these figures.

What the 2018 Mercedes B-Class Fails Its MOT On

Share of the 642 MOT tests on the 2018 Mercedes B-Class that failed at the first attempt in 2025, next to all cars and vans of the same age.

Tyres44%
Same age: 29% (fails on this more often)
Lights and electrics26%
Same age: 27%
Suspension14%
Same age: 19% (fails on this less often)
Windscreen, wipers and mirrors12%
Same age: 16% (fails on this less often)

DVSA anonymised MOT data for 2025; a test that failed on two areas counts in both. How we count it · Mercedes B-Class reliability, common problems and years to avoid

Common Issues to Watch For

These are typical issues for cars of this age, fuel type and engine size, not faults recorded on this model's MOT tests. Use them as a checklist when you view one.

Suspension Wear

Medium risk

Shock absorbers, springs, and anti-roll bar links typically need attention around this age. Listen for clunks over bumps and check for uneven tyre wear.

Service History

Low risk

Always request a full service history. Regular servicing is the single best indicator of how well a car has been maintained, regardless of mileage.

Running Costs Compared

How the 2018 Mercedes B-Class stacks up against similar cars for estimated annual running costs, insurance group, and tax.

Car	Pass Rate	Fuel/yr	Tax/yr	Est. Ins. Group	Total/yr
Mercedes B-Class(2018)	90%	£1,398	£200	Grp 12-25	£1,853
Vauxhall Corsa(2016)	81%	£1,398	£200	Grp 8-20	£2,003+£150
Ford Focus(2016)	87%	£1,398	£275	Grp 12-25	£2,078+£225
Nissan Qashqai(2017)	86%	£1,175	£200	Grp 5-15	£1,780-£73
Volkswagen Polo(2016)	84%	£1,175	£170	Grp 5-15	£1,750-£103

Estimates based on 7,400 miles/year, GOV.UK average pump prices for the week of 19 October 2026, GOV.UK road tax rates and MOT data. Insurance groups are our rough estimate from engine size, not official groups. Actual costs vary by driver, location, and usage.

Questions about the 2018 Mercedes B-Class

Is the 2018 Mercedes B-Class reliable?

Excellent reliability. Very few MOT failures. 90% of MOT tests on 2018 Mercedes B-Classs ended in a pass, from 6,729 tests (DVSA MOT data for tests in 2024, retests included). That's 8 points above the average of 82% across all models in the same data.

How much does a 2018 Mercedes B-Class cost to run?

Our estimate is £1,853 a year (£154 a month): £1,398 fuel, £200 road tax, £55 MOT and £200 predicted repairs, based on 7,400 miles a year. Insurance is not included.

What is the MOT pass rate for a 2018 Mercedes B-Class?

90% of 6,729 MOT tests on the 2018 Mercedes B-Class ended in a pass (DVSA MOT data for tests in 2024, retests included). That ranks it 312th of 607 models first registered in 2018 (bottom half).

Which year Mercedes B-Class has the best MOT pass rate?

Of the years with at least 100 tests, the 2019 Mercedes B-Class has the highest MOT pass rate at 93% and the 2006 the lowest at 71%. Newer cars usually pass more often simply because they are younger and have done fewer miles.

What is the average mileage for a 2018 Mercedes B-Class?

The average mileage recorded at MOT tests on the 2018 Mercedes B-Class is 39,021 miles, which is in line with the expected 44,400 miles for a 6-year-old car, suggesting normal everyday use.