Mercedes GLC (2021)
Estimated running costs and MOT pass rates from 6,414 MOT tests in 2024.
Annual Cost
£2,413
£201/month
MOT Pass Rate
95%
Excellent
Road Tax
£200
Standard rate/year
Est. Insurance
Grp 30-42
2996cc Petrol
Great Choice
95% pass rate, £2,413/year to run. 13 points above average.
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Annual Running Costs
~30 mpg
Standard rate (from April 2017)
Low estimate due to excellent reliability
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
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 GLCs from 2021 ended in a pass in 2024, when they were about 3 years old. That's based on 6,414 tests across the UK, retests included. The average mileage recorded at those tests was 29,460 miles.
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How Does It Compare?
Mileage Analysis
29,460
Average miles
22,200
Expected for age
The average 2021 Mercedes GLC had 29,460 miles on the clock at its 2024 MOT, which is above the expected 22,200 miles for a 3-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 GLC by Year
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About the 2021 Mercedes GLC
The 2021 Mercedes GLC is a premium performance car. Our records list a 2996cc petrol engine, though engines vary between versions. 6,414 MOT tests were recorded on this model in 2024, making it a reasonably common sight on UK roads. It ranks in the top 22% of all 2021 models for MOT pass rate.
With an average of 29,460 miles recorded at its 2024 MOT tests, Mercedes GLC owners cover more miles than the average driver.
2021 Mercedes GLC Fuel Costs
The 2996cc 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 2021 Mercedes GLC?
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 GLC Reliability Trend
Newer Mercedes GLCs pass their MOT more often than older ones, by 4 percentage points on average, which is mostly down to age and wear.
Buying a Used 2021 Mercedes GLC
At 5 years old, the Mercedes GLC offers good value with plenty of life remaining. Most manufacturer warranties will have expired, so a pre-purchase inspection is worth the cost. With 6,414 MOT tests in our data, there's strong statistical confidence in these figures.
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.
Oil Consumption
Low riskLarger 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 riskAlways 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 GLC 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 GLC(2021) | 95% | £1,958 | £200 | Grp 30-42 | £2,413 |
| BMW 5 Series(2019) | 92% | £1,958 | £200 | Grp 30-42 | £2,413same |
| BMW X3(2019) | 92% | £1,958 | £200 | Grp 30-42 | £2,413same |
| BMW X5(2019) | 92% | £1,958 | £200 | Grp 30-42 | £2,413same |
| Audi Q5(2020) | 95% | £1,958 | £200 | Grp 30-42 | £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 2021 Mercedes GLC
Is the 2021 Mercedes GLC reliable?
Excellent reliability. Very few MOT failures. 95% of MOT tests on 2021 Mercedes GLCs ended in a pass, from 6,414 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 2021 Mercedes GLC 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 2021 Mercedes GLC?
95% of 6,414 MOT tests on the 2021 Mercedes GLC ended in a pass (DVSA MOT data for tests in 2024, retests included). That ranks it 711th of 3,336 models first registered in 2021 (top 22%).
Which year Mercedes GLC has the best MOT pass rate?
Of the years with at least 100 tests, the 2021 Mercedes GLC has the highest MOT pass rate at 95% and the 2015 the lowest at 89%. Newer cars usually pass more often simply because they are younger and have done fewer miles.
What is the average mileage for a 2021 Mercedes GLC?
The average mileage recorded at MOT tests on the 2021 Mercedes GLC is 29,460 miles, which is above the expected 22,200 miles for a 3-year-old car. Higher-mileage cars often have more motorway miles, which is generally less harmful than stop-start urban driving.
Related Mercedes Models
Explore other Mercedes cars or similar models in the same category.
Mercedes A
2019 · 1461cc Diesel
Mercedes C
2017 · 1991cc Hybrid
Mercedes A-Class
2017 · 1461cc Diesel
BMW 5 Series
2019 · 2998cc Petrol
BMW X3
2019 · 2998cc Petrol
BMW X5
2019 · 2998cc Petrol
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