Mercedes-Benz C-Class vs Audi A5
Figures updated
The Mercedes-Benz C-Class and Audi A5 are two of the UK's most popular executive cars. We compare the W206 (2021–) C-Class and the B10 (2024–) A5 on price, size, boot space, performance, safety and running costs, plus how reliable each has been across 486,305 real MOT tests.
The short answer
The Audi A5 comes out ahead, with the lower price, the better MOT record and lower fuel costs; the Mercedes-Benz C-Class is close on everything else.
- The Audi A5 is the cheapest to buy new: from £42,760, £4,235 less than the Mercedes-Benz C-Class.
- Their boots are much the same size: Mercedes-Benz C-Class 455 litres, Audi A5 445 litres.
- The Audi A5 has the better MOT record. Like for like on age and mileage, the Mercedes-Benz C-Class fails its MOT about 13% more often.
- The Audi A5 is the cheapest to fuel: comparing petrol versions, about £122 a year less than the Mercedes-Benz C-Class at 7,500 miles a year.
| Figure | Mercedes-Benz C-ClassW206 (2021–), 4-door saloon | Audi A5B10 (2024–), 5-door hatchback |
|---|---|---|
| Price and practicality | ||
| Price newUK list prices, across the range | £46,995 to £62,515September 2026 price list | from £42,760October 2026 price list (best) |
| Body | 4-door saloon | 5-door hatchback |
| Seats | 5 | 5 |
| BootSeats up / folded | 455 litres | 445 litres / 1,299 |
| Length | 4,773mm | 4,829mm |
| WidthWithout mirrors | 1,820mm | 1,860mm |
| Height | 1,443mm | 1,444mm |
| Performance | ||
| Power | 218–258 PS | up to 299 PS (best) |
| 0–62mph | 5.9–7.3 sec | from 5.9 sec |
| Safety | ||
| Euro NCAP ratingTests get tougher each year | ★★★★★ (2022) | ★★★★★ (2024) |
| Economy and emissions | ||
| Fuel types | Diesel, Petrol, Plug-in hybrid | Diesel, Hybrid, Petrol, Plug-in hybrid |
| Official economyVersions of this generation | 25.5–62.8 mpg | 38.7–57.6 mpg |
| CO2 | 10–253 g/km | 46–166 g/km |
| Running costs at 7,500 miles a year | ||
| Petrol or hybrid171.7p a litre, today's UK average | £1,533 (38.2 mpg) | £1,411 (41.5 mpg) (best) |
| Diesel198.4p a litre | £1,221 (55.4 mpg) | £1,221 (55.4 mpg) |
| Cheapest version to fuelWhichever fuel costs least | £1,221 (diesel) | £1,221 (diesel) |
| Car tax a yearCars registered from April 2017 | £200£640 in years 2–6 for versions listed over £40,000 | £200 |
| Reliability from real MOT tests | ||
| Reliability score | 120Well above average | 135Well above average (best) |
| Failed MOT first time (ages 3–20) | 25.5% | 22.0% (best) |
| Failed at 3 years old | 13.1% | 12.7% |
| Failed at 5 years old | 13.8% (best) | 15.0% |
| Failed at 10 years old | 27.1% | 23.8% (best) |
| Most common MOT fault | Ball joint (4.5% of tests) | Tread depth (3.4% of tests) |
| Fails more than average on | Nothing stands out | Nothing stands out |
| MOT tests analysed | 362,136 | 124,169 |
| About the cars | ||
| Type | Executive car | Executive car |
| Owners' average miles a year | 8,900 | 9,300 |
| On sale | 2021 on | 2024 on |
Green marks the better figure where the difference is more than 3%. Reliability figures cover every version of each model tested in the year. Running costs use the typical official economy of recent versions (WLTP where available); real-world economy is usually a little worse for every car.
More comparisons
Frequently asked questions
›Is the Mercedes-Benz C-Class or the Audi A5 more reliable?
The Audi A5. Like for like on age and mileage, the Mercedes-Benz C-Class fails its MOT about 13% more often (reliability scores 135 and 120, where 100 is average). 22.0% of Audi A5s and 25.5% of Mercedes-Benz C-Classes failed first time in 2024.
›Which is bigger, the Mercedes-Benz C-Class or the Audi A5?
The Audi A5 is 56mm longer (4,829mm against 4,773mm). Their boots are much the same: 455 and 445 litres.
›Which is cheaper to buy, the Mercedes-Benz C-Class or the Audi A5?
The Audi A5: new prices start at £42,760, £4,235 less than the Mercedes-Benz C-Class (from £46,995). These are manufacturer list prices; dealers and brokers often sell for less.
›Which is cheaper to run, the Mercedes-Benz C-Class or the Audi A5?
Comparing petrol versions, the Audi A5 costs about £122 a year less to fuel at 7,500 miles (£1,411 against £1,533), using typical official economy and current UK average fuel prices.
›Which is safer, the Mercedes-Benz C-Class or the Audi A5?
Euro NCAP gave the Mercedes-Benz C-Class 5 stars (2022) and the Audi A5 5 stars (2024). Euro NCAP makes its tests tougher every few years, so ratings from different years aren't directly comparable.
›Should I buy the Mercedes-Benz C-Class or the Audi A5?
The Audi A5 comes out ahead, with the lower price, the better MOT record and lower fuel costs; the Mercedes-Benz C-Class is close on everything else. The comparison above sets out price, space, performance, safety, running costs and reliability side by side.
Sources: manufacturers' UK specifications and price lists and Euro NCAP (listed on each model's page); DVSA anonymised MOT tests 2024 (Open Government Licence v3.0); Vehicle Certification Agency car fuel data, © Crown copyright, VCA cannot accept liability for its accuracy; fuel prices from the GOV.UK Fuel Finder scheme. Photos from Wikimedia Commons, credited under each picture.