Mercedes-Benz A-Class vs SEAT Leon
Figures updated
The Mercedes-Benz A-Class and SEAT Leon are two of the UK's most popular family hatchbacks. We compare the W177 (2018–) A-Class and the Mk4 (2020–) Leon on price, size, boot space, performance, safety and running costs, plus how reliable each has been across 523,232 real MOT tests.
The short answer
The SEAT Leon 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 SEAT Leon is the cheapest to buy new: from £25,995, £5,875 less than the Mercedes-Benz A-Class.
- The SEAT Leon has the biggest boot: 380 litres, 30 more than the Mercedes-Benz A-Class.
- The SEAT Leon has the better MOT record. Like for like on age and mileage, the Mercedes-Benz A-Class fails its MOT about 7% more often.
- The SEAT Leon is the cheapest to fuel: comparing petrol versions, about £206 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 | Mercedes-Benz A-ClassW177 (2018–), 5-door hatchback | SEAT LeonMk4 (2020–), 5-door hatchback |
|---|---|---|
| Price and practicality | ||
| Price newUK list prices, across the range | £31,870 to £46,175July 2026 price list | £25,995 to £40,165July 2026 price list (best) |
| Body | 5-door hatchback | 5-door hatchback |
| Seats | 5 | 5 |
| BootSeats up / folded | 350 litres / 1,190 | 380 litres (best) |
| Length | 4,428mm | 4,368mm |
| WidthWithout mirrors | 1,796mm | 1,800mm |
| Height | 1,423mm | 1,456mm |
| Performance | ||
| Power | 136–218 PS (best) | 115–204 PS |
| 0–62mph | 7.4–9.2 sec (best) | 7.7–10.4 sec |
| Safety | ||
| Euro NCAP ratingTests get tougher each year | ★★★★★ (2018) | ★★★★★ (2025) |
| Economy and emissions | ||
| Fuel types | Diesel, Hybrid, Petrol, Plug-in hybrid | Diesel, Petrol, Plug-in hybrid |
| Official economyVersions of this generation | 31.4–64.2 mpg | 47.9–65.7 mpg |
| CO2 | 16–205 g/km | 28–134 g/km |
| Running costs at 7,500 miles a year | ||
| Petrol or hybrid171.7p a litre, today's UK average | £1,368 (42.8 mpg) | £1,162 (50.4 mpg) (best) |
| Diesel198.4p a litre | £1,148 (58.9 mpg) | £1,102 (61.4 mpg) (best) |
| Cheapest version to fuelWhichever fuel costs least | £1,148 (diesel) | £1,102 (diesel) |
| Car tax a yearCars registered from April 2017 | £200£640 in years 2–6 for versions listed over £40,000 | £200£640 in years 2–6 for versions listed over £40,000 |
| Reliability from real MOT tests | ||
| Reliability score | 108Above average | 116Well above average (best) |
| Failed MOT first time (ages 3–20) | 21.4% (best) | 23.6% |
| Failed at 3 years old | 10.2% (best) | 12.3% |
| Failed at 5 years old | 15.0% (best) | 18.3% |
| Failed at 10 years old | 29.7% | 24.3% (best) |
| Most common MOT fault | Tread depth (2.4% of tests) | Coil spring (2.8% of tests) |
| Fails more than average on | Seat belts and airbags (2.7×) | Nothing stands out |
| MOT tests analysed | 341,498 | 181,734 |
| About the cars | ||
| Type | Family hatchback | Family hatchback |
| Owners' average miles a year | 8,500 | 9,400 |
| On sale | 2018 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 Mercedes-Benz A-Class or the SEAT Leon more reliable?
The SEAT Leon. Like for like on age and mileage, the Mercedes-Benz A-Class fails its MOT about 7% more often (reliability scores 116 and 108, where 100 is average). 23.6% of SEAT Leons and 21.4% of Mercedes-Benz A-Classes failed first time in 2024.
›Which is bigger, the Mercedes-Benz A-Class or the SEAT Leon?
The Mercedes-Benz A-Class is 60mm longer (4,428mm against 4,368mm). The SEAT Leon has the bigger boot: 380 litres against 350.
›Which is cheaper to buy, the Mercedes-Benz A-Class or the SEAT Leon?
The SEAT Leon: new prices start at £25,995, £5,875 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 Mercedes-Benz A-Class or the SEAT Leon?
Comparing petrol versions, the SEAT Leon costs about £206 a year less to fuel at 7,500 miles (£1,162 against £1,368), using typical official economy and current UK average fuel prices.
›Which is safer, the Mercedes-Benz A-Class or the SEAT Leon?
Euro NCAP gave the Mercedes-Benz A-Class 5 stars (2018) and the SEAT Leon 5 stars (2025). Euro NCAP makes its tests tougher every few years, so ratings from different years aren't directly comparable.
›Should I buy the Mercedes-Benz A-Class or the SEAT Leon?
The SEAT Leon 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.