Is the 2021 MERCEDES C reliable?

Excellent reliability. Very few MOT failures. 92% of MERCEDES Cs from 2021 passed their MOT first time in 2026, based on 3,772 tests. That's 10 points above the national average of 82%.

How much does a 2021 MERCEDES C cost to run?

Estimated annual running cost is £1,777 (£148/month), including £1327 fuel, £195 road tax, £55 MOT, and £200 predicted repairs.

What is the MOT pass rate for a 2021 MERCEDES C?

The 2021 MERCEDES C has a 92% MOT pass rate based on 3,772 tests in 2026. This ranks 1814 out of 3373 cars from 2021.

Which year MERCEDES C is most reliable?

The 2020 MERCEDES C has the highest MOT pass rate at 92%. The least reliable year is 2004 at 72%.

MERCEDES C (2021)

Q: What is the average mileage for a 2021 MERCEDES C?

The average mileage for a 2021 MERCEDES C is 27,184 miles, which is below the expected 37,000 miles for a 5-year-old car. This suggests lighter use than average, which generally means less wear on major components.

Running costs, reliability data, and common problems from 3,772 real MOT tests.

Annual Cost

£1,777

£148/month

MOT Pass Rate

92%

Excellent

Road Tax

£195

Flat rate/year

Insurance

Grp 18-32

1991cc Hybrid

Great Choice

92% pass rate, £1777/year to run. 10 points above average.

Buying this car? Check for finance, write-offs & theft

£4.99

Check a specific MERCEDES C

Enter a reg plate for full MOT history, mileage check, health score, running costs, and reliability data. Free, instant, no signup.

Hybrid1991cc5 years old3,772 tests27k miles avg

Annual Running Costs

Fuel (Hybrid, 1991cc)

~36 mpg

£1,327

Road Tax

Flat rate (post-2017)

£195

MOT Test

£55

Predicted Repairs

Low estimate due to excellent reliability

£200

Total per year£1,777

Per month£148/mo

Per week£34/wk

Based on 7,400 miles/year (UK average), current fuel prices, and repair likelihood from MOT data. Insurance not included.

🛡️

Get an insurance quote for this MERCEDES C

Compare quotes and find the best deal

Reliability Verdict

92% MOT pass rate(Excellent)

0%National avg: 82%100%

Excellent reliability. Very few MOT failures. That's 10 points above the national average of 82%. It also outperforms the MERCEDES brand average of 87%.

At 5 years old, 92% of MERCEDES Cs from 2021 passed their MOT first time in 2026. That's based on 3,772 tests across the UK. The average mileage at this age is 27,184 miles.

Got a MERCEDES C you're looking at?

Enter the reg plate to check its specific MOT history, mileage, and health score.

How Does It Compare?

Rank among 2021 cars1814th of 3,373(top 54%)

Rank among MERCEDES models456th of 1,408(top 32%)

vs national average+10%(82% avg)

vs 2021 cars average+0%(92% avg)

vs MERCEDES average+5%(87% avg)

Mileage Analysis

27,184

Average miles

37,000

Expected for age

The average 2021 MERCEDES C has 27,184 miles on the clock, which is below the expected 37,000 miles for a 5-year-old car. This suggests lighter use than average, which generally means less wear on major components.

Looking at a specific MERCEDES C?

Enter its reg plate for a free check with full MOT history, mileage verification, and predicted costs.

Best Year to Buy?

The most reliable year is the 2020 model with a 92% MOT pass rate, while the 2004 model has the lowest at 72%. The 2021 sits between the two at 92%.

MERCEDES C by Year

Year	Pass Rate	Tests	Avg Mileage
2021	92%	3,772	27,184 mi
2020	92%	16,225	33,734 mi
2019	91%	52,838	40,700 mi
2018	90%	62,138	51,166 mi
2017	89%	87,612	60,957 mi
2016	88%	80,181	73,695 mi
2015	86%	71,635	85,216 mi
2014	85%	54,729	90,129 mi
2013	81%	51,703	97,102 mi
2012	79%	59,235	102,461 mi
2011	79%	42,676	109,800 mi
2010	78%	28,538	111,322 mi
2009	77%	28,440	118,861 mi
2008	77%	30,369	121,672 mi
2007	76%	25,544	119,028 mi
2006	74%	20,205	118,301 mi
2005	73%	17,978	121,824 mi
2004	72%	13,493	116,683 mi
2003	73%	9,158	112,103 mi
2002	75%	4,985	103,944 mi
2001	75%	2,463	101,994 mi
2000	77%	1,103	104,741 mi
1999	82%	2,683	110,180 mi
1998	79%	2,916	112,877 mi
1997	81%	2,336	121,767 mi
1996	82%	1,296	107,809 mi
1995	83%	1,017	101,913 mi
1994	84%	735	103,968 mi
1993	82%	71	105,975 mi
1992	87%	30	131,044 mi
1991	79%	47	112,139 mi
1990	66%	41	103,332 mi

Similar Cars to Consider

TOYOTA YARIS

2019 · 1497cc Hybrid

£1,582/year

93%

+1%

MINI COOPER S

2019 · 1499cc Hybrid

£1,582/year

92%

same

LAND ROVER RANGE ROVER SPORT

2019 · 1997cc Hybrid

£1,772/year

94%

+2%

TOYOTA C-HR

2019 · 1987cc Hybrid

£1,772/year

92%

same

Check a Specific Mercedes C

Enter a reg plate to get the full MOT history, health score, and mileage verification.

Upgrade to Premium (£4.99) for stolen, finance, and write-off checks.

About the 2021 MERCEDES C

The 2021 MERCEDES C is a family car with a 1991cc hybrid engine. 3,772 of these vehicles were MOT tested in 2026, making it a reasonably common sight on UK roads. Among all cars from 2021, the average MOT pass rate is 92%, and this model falls short of that benchmark.

With an average of 27,184 miles at 5 years old, MERCEDES C owners tend to use this car less than the typical driver.

2021 MERCEDES C Fuel Costs

The 1991cc hybrid engine offers a reasonable balance between performance and economy. Expect around 36 mpg in mixed driving, which works out to roughly £1,327 per year at current hybrid prices of 142p per litre (based on 7,400 miles per year). As a hybrid, real-world fuel costs will vary significantly depending on how much electric-only driving you do.

What does it cost to own a 2021 MERCEDES C?

Total estimated annual running cost is £1,777 (£148/month), broken down as £1327 fuel, £195 road tax, £55 MOT, and £200 predicted repairs. The low repair estimate reflects the excellent 92% pass rate. These cars rarely fail their MOT, so unexpected bills are less likely.

MERCEDES C Reliability Trend

Newer MERCEDES Cs show better MOT pass rates than older ones, with an average improvement of 6 percentage points.

Buying a Used 2021 MERCEDES C

At 5 years old, the MERCEDES C offers good value with plenty of life remaining. Most manufacturer warranties will have expired, so a pre-purchase inspection is worth the cost. If you're flexible on year, the 2020 model has the highest pass rate at 92%.

Common Issues to Watch For

Based on the 2021 MERCEDES C's fuel type, age, and engine size, these are the most likely problem areas to check.

Hybrid Battery Health

Medium risk

After 5 years, hybrid battery capacity may have reduced. A full replacement costs £2,000-£4,000, though reconditioning is cheaper at £500-£1,500.

Inverter and Power Electronics

Low risk

The inverter converts DC to AC for the electric motor. Failures are expensive (£1,500+) but relatively rare. Listen for unusual buzzing sounds.

Regenerative Braking

Medium risk

Brake discs can corrode from reduced use (the electric motor handles most braking). Surface rust is normal but deep pitting needs attention.

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 2021 MERCEDES C stacks up against similar cars for annual running costs, insurance, and tax.

Car	Pass Rate	Fuel/yr	Tax/yr	Insurance	Total/yr
MERCEDES C(2021)	92%	£1327	£195	Grp 18-32	£1777
TOYOTA YARIS(2019)	93%	£1137	£190	Grp 12-25	£1582-£195
MINI COOPER S(2019)	92%	£1137	£190	Grp 12-25	£1582-£195
LAND ROVER RANGE ROVER SPORT(2019)	94%	£1327	£190	Grp 18-32	£1772-£5
TOYOTA C-HR(2019)	92%	£1327	£190	Grp 18-32	£1772-£5

Estimates based on 7,400 miles/year, current fuel prices, and MOT data. Insurance groups are indicative. Actual costs vary by driver, location, and usage.