Audi A4 vs Mercedes-Benz E-Class
Figures updated
The Audi A4 and Mercedes-Benz E-Class are two of the UK's most popular executive cars. We compare the B9 (2015–2024) A4 and the W214 (2023–) E-Class on price, size, boot space, performance, safety and running costs, plus how reliable each has been across 475,887 real MOT tests.
The short answer
Pick the Audi A4 for lower fuel costs, or the Mercedes-Benz E-Class for the bigger boot and the better MOT record.
- The Mercedes-Benz E-Class has the biggest boot: 540 litres, 80 more than the Audi A4.
- The Mercedes-Benz E-Class has the better MOT record. Like for like on age and mileage, the Audi A4 fails its MOT about 6% more often.
- The Audi A4 is the cheapest to fuel: comparing diesel versions, about £382 a year less than the Mercedes-Benz E-Class at 7,500 miles a year.
- Watch the wheels on a Mercedes-Benz E-Class: it fails on them 2.9 times as often as the average car.
| Figure | Audi A4B9 (2015–2024), 4-door saloon | Mercedes-Benz E-ClassW214 (2023–), 4-door saloon |
|---|---|---|
| Price and practicality | ||
| Price newUK list prices, across the range | – | £57,170 to £88,520June 2026 price list |
| Body | 4-door saloon | 4-door saloon |
| Seats | 5 | 5 |
| BootSeats up / folded | 460 litres | 540 litres (best) |
| Length | 4,762mm | 4,949mm |
| WidthWithout mirrors | 1,847mm | 1,904mm |
| Height | 1,387mm | 1,468mm |
| Performance | ||
| Power | 136–265 PS | 197–313 PS (best) |
| 0–62mph | 5.5–9.5 sec (best) | 6.4–7.6 sec |
| Safety | ||
| Euro NCAP ratingTests get tougher each year | ★★★★★ (2015) | ★★★★★ (2024) |
| Economy and emissions | ||
| Fuel types | Diesel | Diesel, Petrol, Plug-in hybrid |
| Official economyVersions of this generation | 54.3–74.3 mpg | 23.3–60.1 mpg |
| CO2 | 99–137 g/km | 11–276 g/km |
| Running costs at 7,500 miles a year | ||
| Petrol or hybrid171.4p a litre, today's UK average | – | £1,760 (33.2 mpg) |
| Diesel198.4p a litre | £1,030 (65.7 mpg) (best) | £1,412 (47.9 mpg) |
| Cheapest version to fuelWhichever fuel costs least | £1,030 (diesel) | £1,412 (diesel) |
| Car tax, registered 2001 to 2017Taxed on CO2; newer cars pay a flat £200 | £20 to £790 | £20 to £790 |
| Reliability from real MOT tests | ||
| Reliability score | 125Well above average | 133Well above average (best) |
| Failed MOT first time (ages 3–20) | 27.1% | 22.5% (best) |
| Failed at 3 years old | 11.8% (best) | 13.3% |
| Failed at 5 years old | 14.5% | 14.7% |
| Failed at 10 years old | 26.3% | 25.1% (best) |
| Most common MOT fault | Coil spring (3.6% of tests) | Tread depth (2.7% of tests) |
| Fails more than average on | Nothing stands out | Wheels (2.9×) |
| MOT tests analysed | 244,913 | 230,974 |
| About the cars | ||
| Type | Executive car | Executive car |
| Owners' average miles a year | 9,900 | 10,600 |
| On sale | 2015–2024 | 2023 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 Audi A4 or the Mercedes-Benz E-Class more reliable?
The Mercedes-Benz E-Class. Like for like on age and mileage, the Audi A4 fails its MOT about 6% more often (reliability scores 133 and 125, where 100 is average). 22.5% of Mercedes-Benz E-Classes and 27.1% of Audi A4s failed first time in 2024.
›Which is bigger, the Audi A4 or the Mercedes-Benz E-Class?
The Mercedes-Benz E-Class is 187mm longer (4,949mm against 4,762mm). The Mercedes-Benz E-Class has the bigger boot: 540 litres against 460.
›Which is cheaper to run, the Audi A4 or the Mercedes-Benz E-Class?
Comparing diesel versions, the Audi A4 costs about £382 a year less to fuel at 7,500 miles (£1,030 against £1,412), using typical official economy and current UK average fuel prices.
›Which is safer, the Audi A4 or the Mercedes-Benz E-Class?
Euro NCAP gave the Audi A4 5 stars (2015) and the Mercedes-Benz E-Class 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 Audi A4 or the Mercedes-Benz E-Class?
Pick the Audi A4 for lower fuel costs, or the Mercedes-Benz E-Class for the bigger boot and the better MOT record. 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.