Audi A6 vs BMW 4 Series
Figures updated
The Audi A6 and BMW 4 Series are two of the UK's most popular executive cars. We compare the C9 (2025–) A6 and the G22 (2020–) 4 Series on price, size, boot space, performance, safety and running costs, plus how reliable each has been across 226,570 real MOT tests.
The short answer
Pick the Audi A6 for the bigger boot and the better MOT record, or the BMW 4 Series for the lower price and more performance.
- The BMW 4 Series is the cheapest to buy new: from £46,180, £7,880 less than the Audi A6.
- The Audi A6 has the biggest boot: 492 litres, 52 more than the BMW 4 Series.
- The Audi A6 has the better MOT record. Like for like on age and mileage, the BMW 4 Series fails its MOT about 12% more often.
- Running costs are close: the petrol versions cost within £10 a year of each other to fuel at 7,500 miles a year.
- Watch the tyres on a BMW 4 Series: it fails on them 1.3 times as often as the average car.
| Figure | Audi A6C9 (2025–), 4-door saloon | BMW 4 SeriesG22 (2020–), 2-door coupé |
|---|---|---|
| Price and practicality | ||
| Price newUK list prices, across the range | from £54,060October 2026 price list | £46,180 to £63,385July 2026 price list (best) |
| Body | 4-door saloon | 2-door coupé |
| Seats | 5 (best) | 4 |
| BootSeats up / folded | 492 litres (best) | 440 litres |
| Length | 4,999mm | 4,768mm |
| WidthWithout mirrors | 1,875mm | 1,852mm |
| Height | 1,452mm | 1,383mm |
| Performance | ||
| Power | 204–299 PS | 184–374 PS (best) |
| 0–62mph | 6.0–8.2 sec | 4.5–7.5 sec (best) |
| Safety | ||
| Euro NCAP ratingTests get tougher each year | ★★★★★ (2024) | ★★★★★ (2019) |
| Economy and emissions | ||
| Fuel types | Electric, Hybrid, Petrol, Plug-in hybrid | Petrol |
| Official economyVersions of this generation | 36.2–55.4 mpg | 32.8–42.8 mpg |
| CO2 | 32–178 g/km | 144–186 g/km |
| Electric range | 329–462 miles | – |
| Running costs at 7,500 miles a year | ||
| Petrol or hybrid171.7p a litre, today's UK average | £1,449 (40.4 mpg) | £1,453 (40.3 mpg) |
| Electric, charged at home26.3p per kWh standard tariff | £548 (4 mi/kWh) | – |
| Cheapest version to fuelWhichever fuel costs least | £548 (electric) | £1,453 (petrol) |
| Car tax a yearCars registered from April 2017 | £200 | £200£640 in years 2–6 for versions listed over £40,000 |
| Reliability from real MOT tests | ||
| Reliability score | 155Well above average (best) | 138Well above average |
| Failed MOT first time (ages 3–20) | 20.9% | 16.4% (best) |
| Failed at 3 years old | 9.5% (best) | 13.1% |
| Failed at 5 years old | 11.2% (best) | 14.0% |
| Failed at 10 years old | 20.5% (best) | 21.6% |
| Most common MOT fault | Tread depth (2.9% of tests) | Condition (2.4% of tests) |
| Fails more than average on | Nothing stands out | Tyres (1.3×) |
| MOT tests analysed | 122,625 | 103,945 |
| About the cars | ||
| Type | Executive car | Executive car |
| Owners' average miles a year | 11,000 | 9,200 |
| On sale | 2025 on | 2020 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 A6 or the BMW 4 Series more reliable?
The Audi A6. Like for like on age and mileage, the BMW 4 Series fails its MOT about 12% more often (reliability scores 155 and 138, where 100 is average). 20.9% of Audi A6s and 16.4% of BMW 4 Serieses failed first time in 2024.
›Which is bigger, the Audi A6 or the BMW 4 Series?
The Audi A6 is 231mm longer (4,999mm against 4,768mm). The Audi A6 has the bigger boot: 492 litres against 440.
›Which is cheaper to buy, the Audi A6 or the BMW 4 Series?
The BMW 4 Series: new prices start at £46,180, £7,880 less than the Audi A6 (from £54,060). These are manufacturer list prices; dealers and brokers often sell for less.
›Which is cheaper to run, the Audi A6 or the BMW 4 Series?
Comparing petrol versions, fuel costs are within £10 a year of each other at 7,500 miles, using typical official economy and current UK average fuel prices.
›Which is safer, the Audi A6 or the BMW 4 Series?
Euro NCAP gave the Audi A6 5 stars (2024) and the BMW 4 Series 5 stars (2019). Euro NCAP makes its tests tougher every few years, so ratings from different years aren't directly comparable.
›Should I buy the Audi A6 or the BMW 4 Series?
Pick the Audi A6 for the bigger boot and the better MOT record, or the BMW 4 Series for the lower price and more performance. 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.