BMW 3 Series vs Audi A6
Figures updated
The BMW 3 Series and Audi A6 are two of the UK's most popular executive cars. We compare the 3 Series G20 (2019–) and the C9 (2025–) A6 on price, size, boot space, performance, safety and running costs, plus how reliable each has been across 576,017 real MOT tests.
The short answer
Pick the BMW 3 Series for the lower price and more performance, or the Audi A6 for the better MOT record.
- The BMW 3 Series is the cheapest to buy new: from £41,945, £12,115 less than the Audi A6.
- Their boots are much the same size: BMW 3 Series 480 litres, Audi A6 492 litres.
- The Audi A6 has the better MOT record. Like for like on age and mileage, the BMW 3 Series fails its MOT about 16% 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 wheels on a BMW 3 Series: it fails on them 2.3 times as often as the average car.
| Figure | BMW 3 Series3 Series G20 (2019–), 4-door saloon | Audi A6C9 (2025–), 4-door saloon |
|---|---|---|
| Price and practicality | ||
| Price newUK list prices, across the range | £41,945 to £66,475July 2026 price list (best) | from £54,060October 2026 price list |
| Body | 4-door saloon | 4-door saloon |
| Seats | 5 | 5 |
| BootSeats up / folded | 480 litres | 492 litres |
| Length | 4,709mm | 4,999mm |
| WidthWithout mirrors | 1,827mm | 1,875mm |
| Height | 1,435mm | 1,452mm |
| Performance | ||
| Power | 150–374 PS (best) | 204–299 PS |
| 0–62mph | 4.4–8.4 sec (best) | 6.0–8.2 sec |
| Safety | ||
| Euro NCAP ratingTests get tougher each year | ★★★★★ (2019) | ★★★★★ (2024) |
| Economy and emissions | ||
| Fuel types | Petrol, Plug-in hybrid | Electric, Hybrid, Petrol, Plug-in hybrid |
| Official economyVersions of this generation | 32.8–42.1 mpg | 36.2–55.4 mpg |
| CO2 | 19–182 g/km | 32–178 g/km |
| Electric range | – | 329–462 miles |
| Running costs at 7,500 miles a year | ||
| Petrol or hybrid171.5p a litre, today's UK average | £1,451 (40.3 mpg) | £1,447 (40.4 mpg) |
| Electric, charged at home26.3p per kWh standard tariff | – | £548 (4 mi/kWh) |
| Cheapest version to fuelWhichever fuel costs least | £1,451 (petrol) | £548 (electric) |
| 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 | 134Well above average | 155Well above average (best) |
| Failed MOT first time (ages 3–20) | 24.5% | 20.9% (best) |
| Failed at 3 years old | 14.0% | 9.5% (best) |
| Failed at 5 years old | 13.4% | 11.2% (best) |
| Failed at 10 years old | 24.8% | 20.5% (best) |
| Most common MOT fault | Tread depth (2.8% of tests) | Tread depth (2.9% of tests) |
| Fails more than average on | Wheels (2.3×) | Nothing stands out |
| MOT tests analysed | 453,392 | 122,625 |
| About the cars | ||
| Type | Executive car | Executive car |
| Owners' average miles a year | 9,700 | 11,000 |
| On sale | 2019 on | 2025 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 BMW 3 Series or the Audi A6 more reliable?
The Audi A6. Like for like on age and mileage, the BMW 3 Series fails its MOT about 16% more often (reliability scores 155 and 134, where 100 is average). 20.9% of Audi A6s and 24.5% of BMW 3 Serieses failed first time in 2024.
›Which is bigger, the BMW 3 Series or the Audi A6?
The Audi A6 is 290mm longer (4,999mm against 4,709mm). Their boots are much the same: 480 and 492 litres.
›Which is cheaper to buy, the BMW 3 Series or the Audi A6?
The BMW 3 Series: new prices start at £41,945, £12,115 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 BMW 3 Series or the Audi A6?
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 BMW 3 Series or the Audi A6?
Euro NCAP gave the BMW 3 Series 5 stars (2019) and the Audi A6 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 BMW 3 Series or the Audi A6?
Pick the BMW 3 Series for the lower price and more performance, or the Audi A6 for 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.