Audi A3 vs Mercedes-Benz A-Class
Figures updated
The Audi A3 and Mercedes-Benz A-Class are two of the UK's most popular family hatchbacks. We compare the A3 8Y Sportback (2020–) and the W177 (2018–) A-Class on price, size, boot space, performance, safety and running costs, plus how reliable each has been across 752,170 real MOT tests.
The short answer
The Audi A3 comes out ahead, with the lower price, the bigger boot, the better MOT record and lower fuel costs; the Mercedes-Benz A-Class is close on everything else.
- The Audi A3 is the cheapest to buy new: from £28,650, £3,220 less than the Mercedes-Benz A-Class.
- The Audi A3 has the biggest boot: 380 litres, 30 more than the Mercedes-Benz A-Class.
- The Audi A3 has the better MOT record. Like for like on age and mileage, the Mercedes-Benz A-Class fails its MOT about 15% more often.
- The Audi A3 is the cheapest to fuel: comparing petrol versions, about £249 a year less than the Mercedes-Benz A-Class at 7,500 miles a year.
- Watch the seat belts and airbags on a Mercedes-Benz A-Class: it fails on them 2.7 times as often as the average car.
| Figure | Audi A3A3 8Y Sportback (2020–), 5-door hatchback (Sportback) | Mercedes-Benz A-ClassW177 (2018–), 5-door hatchback |
|---|---|---|
| Price and practicality | ||
| Price newUK list prices, across the range | from £28,650June 2026 price list (best) | £31,870 to £46,175July 2026 price list |
| Body | 5-door hatchback (Sportback) | 5-door hatchback |
| Seats | 5 | 5 |
| BootSeats up / folded | 380 litres / 1,200 (best) | 350 litres / 1,190 |
| Length | 4,343mm | 4,428mm |
| WidthWithout mirrors | – | 1,796mm |
| Height | – | 1,423mm |
| Performance | ||
| Power | 110–204 PS | 136–218 PS (best) |
| 0–62mph | 7.4–10.6 sec | 7.4–9.2 sec |
| Safety | ||
| Euro NCAP ratingTests get tougher each year | ★★★★★ (2020) | ★★★★★ (2018) |
| Economy and emissions | ||
| Fuel types | Diesel, Hybrid, Petrol, Plug-in hybrid | Diesel, Hybrid, Petrol, Plug-in hybrid |
| Official economyVersions of this generation | 50.4–58.9 mpg | 31.4–64.2 mpg |
| CO2 | 6–128 g/km | 16–205 g/km |
| Running costs at 7,500 miles a year | ||
| Petrol or hybrid171.7p a litre, today's UK average | £1,119 (52.3 mpg) (best) | £1,368 (42.8 mpg) |
| Diesel198.4p a litre | £1,148 (58.9 mpg) | £1,148 (58.9 mpg) |
| Cheapest version to fuelWhichever fuel costs least | £1,119 (petrol) | £1,148 (diesel) |
| 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 | 124Well above average (best) | 108Above average |
| Failed MOT first time (ages 3–20) | 24.9% | 21.4% (best) |
| Failed at 3 years old | 10.7% | 10.2% (best) |
| Failed at 5 years old | 12.3% (best) | 15.0% |
| Failed at 10 years old | 23.6% (best) | 29.7% |
| Most common MOT fault | Tread depth (2.9% of tests) | Tread depth (2.4% of tests) |
| Fails more than average on | Nothing stands out | Seat belts and airbags (2.7×) |
| MOT tests analysed | 410,672 | 341,498 |
| About the cars | ||
| Type | Family hatchback | Family hatchback |
| Owners' average miles a year | 8,900 | 8,500 |
| On sale | 2020 on | 2018 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 A3 or the Mercedes-Benz A-Class more reliable?
The Audi A3. Like for like on age and mileage, the Mercedes-Benz A-Class fails its MOT about 15% more often (reliability scores 124 and 108, where 100 is average). 24.9% of Audi A3s and 21.4% of Mercedes-Benz A-Classes failed first time in 2024.
›Which is bigger, the Audi A3 or the Mercedes-Benz A-Class?
The Mercedes-Benz A-Class is 85mm longer (4,428mm against 4,343mm). The Audi A3 has the bigger boot: 380 litres against 350.
›Which is cheaper to buy, the Audi A3 or the Mercedes-Benz A-Class?
The Audi A3: new prices start at £28,650, £3,220 less than the Mercedes-Benz A-Class (from £31,870). These are manufacturer list prices; dealers and brokers often sell for less.
›Which is cheaper to run, the Audi A3 or the Mercedes-Benz A-Class?
Comparing petrol versions, the Audi A3 costs about £249 a year less to fuel at 7,500 miles (£1,119 against £1,368), using typical official economy and current UK average fuel prices.
›Which is safer, the Audi A3 or the Mercedes-Benz A-Class?
Euro NCAP gave the Audi A3 5 stars (2020) and the Mercedes-Benz A-Class 5 stars (2018). Euro NCAP makes its tests tougher every few years, so ratings from different years aren't directly comparable.
›Should I buy the Audi A3 or the Mercedes-Benz A-Class?
The Audi A3 comes out ahead, with the lower price, the bigger boot, the better MOT record and lower fuel costs; the Mercedes-Benz A-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.