Mercedes S-Class (2020)

Estimated running costs and MOT pass rates from 540 MOT tests in 2024.

Annual Cost

£2,413

£201/month

MOT Pass Rate

95%

Excellent

Road Tax

£200

Standard rate/year

Est. Insurance

Grp 35-50

3982cc Petrol

Great Choice

95% pass rate, £2,413/year to run. 13 points above average.

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Petrol3982cc6 years old540 tests44k miles avg

Annual Running Costs

Fuel (Petrol, 3982cc)

~30 mpg

£1,958

Road Tax

Standard rate (from April 2017)

£200

MOT Test

£55

Predicted Repairs

Low estimate due to excellent reliability

£200

Total per year£2,413

Per month£201/mo

Per week£46/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

95% MOT pass rate(Excellent)

0%All-model avg: 82%100%

Excellent reliability. Very few MOT failures. That's 13 points above the average of 82% across all models in our data. It also outperforms the Mercedes brand average of 87%.

95% of MOT tests on Mercedes S-Classs from 2020 ended in a pass in 2024, when they were about 4 years old. That's based on 540 tests across the UK, retests included. The average mileage recorded at those tests was 43,972 miles.

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How Does It Compare?

Rank among 2020 models492nd of 2,554(top 20%)

Rank among Mercedes models236th of 1,376(top 18%)

vs average of all models+13%(82% avg)

vs 2020 models average+3%(92% avg)

vs Mercedes average+8%(87% avg)

Mileage Analysis

43,972

Average miles

29,600

Expected for age

The average 2020 Mercedes S-Class had 43,972 miles on the clock at its 2024 MOT, which is above the expected 29,600 miles for a 4-year-old car. Higher-mileage cars often have more motorway miles, which is generally less harmful than stop-start urban driving.

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Mercedes S-Class by Year

Year	Pass Rate	Tests	Avg Mileage
2021	91%	164	32,036 mi
2020	95%	540	43,972 mi
2019	94%	5,921	67,860 mi
2018	94%	6,518	75,456 mi
2017	93%	5,990	73,988 mi
2016	91%	6,819	74,260 mi
2015	92%	5,513	87,325 mi
2014	92%	3,915	95,545 mi
2013	89%	2,145	108,065 mi
2012	88%	2,817	100,420 mi
2011	87%	2,202	117,628 mi
2010	85%	2,001	110,934 mi
2009	82%	1,990	114,274 mi
2008	84%	2,232	110,584 mi
2007	84%	2,940	117,418 mi
2006	87%	2,334	111,043 mi
2005	84%	1,301	132,014 mi
2004	82%	1,158	124,020 mi
2003	82%	1,227	120,882 mi
2002	79%	720	115,052 mi
2001	79%	735	107,381 mi
2000	81%	562	102,703 mi
1999	78%	434	98,447 mi
1998	81%	522	111,371 mi
1997	86%	373	107,182 mi
1996	83%	348	109,185 mi
1995	86%	286	111,087 mi
1994	92%	140	106,787 mi
1993	76%	49	112,335 mi
1992	72%	121	119,350 mi
1991	92%	118	120,508 mi
1990	87%	125	142,121 mi

Similar Cars to Consider

Mercedes C

2019 · 3982cc Petrol

£2,413/year

91%

-4%

Porsche Cayenne

2019 · 3996cc Petrol

£2,413/year

95%

same

Porsche 911

2018 · 3996cc Petrol

£2,413/year

96%

+1%

Audi A6

2020 · 3996cc Petrol

£2,413/year

94%

-1%

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About the 2020 Mercedes S-Class

The 2020 Mercedes S-Class is a premium performance car. Our records list a 3982cc petrol engine, though engines vary between versions. 540 MOT tests were recorded on this model in 2024, making it a less common model in the UK market. It ranks in the top 20% of all 2020 models for MOT pass rate.

With an average of 43,972 miles recorded at its 2024 MOT tests, Mercedes S-Class owners cover more miles than the average driver.

2020 Mercedes S-Class Fuel Costs

The 3982cc petrol engine is on the larger side, so fuel won't be this car's strong point. Expect around 30 mpg in mixed driving, which works out to roughly £1,958 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 2020 Mercedes S-Class?

Total estimated annual running cost is £2,413 (£201/month), broken down as £1,958 fuel, £200 road tax, £55 MOT, and £200 predicted repairs. The low repair estimate reflects the excellent 95% pass rate. These cars rarely fail their MOT, so unexpected bills are less likely.

Mercedes S-Class Reliability Trend

Newer Mercedes S-Classs pass their MOT more often than older ones, by 6 percentage points on average, which is mostly down to age and wear.

Buying a Used 2020 Mercedes S-Class

At 6 years old, the Mercedes S-Class offers good value with plenty of life remaining. Most manufacturer warranties will have expired, so a pre-purchase inspection is worth the cost.

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.

Timing Chain / Belt

Watch out

At 6 years old, check whether the timing belt has been replaced (typically due every 5-7 years or 60,000-100,000 miles). A snapped belt can destroy the engine.

Oil Consumption

Low risk

Larger petrol engines can develop higher oil consumption as they age. Check the oil level and look for blue smoke from the exhaust.

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 2020 Mercedes S-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 S-Class(2020)	95%	£1,958	£200	Grp 35-50	£2,413
Mercedes C(2019)	91%	£1,958	£200	Grp 35-50	£2,413same
Porsche Cayenne(2019)	95%	£1,958	£200	Grp 35-50	£2,413same
Porsche 911(2018)	96%	£1,958	£200	Grp 35-50	£2,413same
Audi A6(2020)	94%	£1,958	£200	Grp 35-50	£2,413same

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 2020 Mercedes S-Class

Is the 2020 Mercedes S-Class reliable?

Excellent reliability. Very few MOT failures. 95% of MOT tests on 2020 Mercedes S-Classs ended in a pass, from 540 tests (DVSA MOT data for tests in 2024, retests included). That's 13 points above the average of 82% across all models in the same data.

How much does a 2020 Mercedes S-Class cost to run?

Our estimate is £2,413 a year (£201 a month): £1,958 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 2020 Mercedes S-Class?

95% of 540 MOT tests on the 2020 Mercedes S-Class ended in a pass (DVSA MOT data for tests in 2024, retests included). That ranks it 492nd of 2,554 models first registered in 2020 (top 20%).

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

Of the years with at least 100 tests, the 2020 Mercedes S-Class has the highest MOT pass rate at 95% and the 1992 the lowest at 72%. Newer cars usually pass more often simply because they are younger and have done fewer miles.

What is the average mileage for a 2020 Mercedes S-Class?

The average mileage recorded at MOT tests on the 2020 Mercedes S-Class is 43,972 miles, which is above the expected 29,600 miles for a 4-year-old car. Higher-mileage cars often have more motorway miles, which is generally less harmful than stop-start urban driving.