Used Audi A3 review: 2012 to 2020 (Mk3) - Running costs, MPG, CO2 emissions and insurance

The Audi A3 can be quite cheap to run, thanks to a range of engines that includes some rather frugal diesels, and even the petrol options are really economical, especially in later cars with the 1.0-litre three-cylinder motor.

There’s even a plug-in hybrid option that can drive on electric power alone, which means people who can plug in at home have the option of doing daily trips without using any fuel at all. However, as with all A3s, it’s not the most affordable model to buy in the first place.

How much does a used Audi A3 cost?

You can check our sister site Buyacar for latest prices on a used Audi A3, but in general it will cost around the same as a BMW 1 Series or Mercedes A-Class, its core rivals when new.

The Audi A3 was priced higher when new than an equivalent SEAT Leon, Volkswagen Golf or Skoda Octavia - all cars it shares parts with - but the list of standard equipment fitted is long and the feeling of quality is undeniable. Furthermore, A3s are an appealing used buy, so the Audi retains its value better.

This means that while it’s not the best value for money in terms of purchase price, especially next to its siblings above, it won’t lose quite so much value over your ownership.

What’s it like for fuel economy, emissions and tax?

If you want the lowest running costs with your A3, go for the 1.6-litre TDI diesel. Official figures say it’s capable of more than 70mpg and, with CO2 emissions of just 99g/km on some models, tax is free for cars first registered before April 2017. In later models, the figures were revised to 54.3mpg and CO2 emissions of between 138-143g/km thanks to changes in how they’re measured.

In later post-2016 cars, the 148bhp 2.0-litre 35 TDI diesel engine is the best. It’s one of our favourite engines in the line-up, offering claimed fuel economy of 56.5mpg and CO2 emissions of 131g/km while being capable of hitting 0-62mph in 8.6 seconds.

There’s also an even more efficient A3 Ultra, which emits 89g/km and returns up to a claimed 83mpg. You’ll pay much more in tax for petrol models, although the less powerful engines have fuel-economy figures that aren’t far off some of the diesels. It costs £155 a year in VED (road tax) for models built after 1 April 2017.

The petrol-engined A3s are also remarkably frugal. Drivers covering a lower yearly mileage ought to consider the 148bhp 1.5-litre 35 TFSI. Its clever cylinder-deactivation system, which shuts down parts of the engine when full power isn’t required, helps it to return 44.8mpg and emit 142g/km of CO2. 

The 114bhp 1.0-litre three-cylinder 30 TFSI engine is even more economical, returning up to 49.6mpg and even lower CO2 emissions. You might miss the 1.5-litre engine’s power, though. The 2.0-litre petrol engine is powerful but not very economical, and in older models the 1.2-litre engine is similar to the later 1.0-litre as the lowest-cost option. The 1.4-litre motor is also really similar to the 1.5-litre in later cars.

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The plug-in hybrid Audi A3 e-tron has an official economy figure of 141.2mpg, and CO2 emissions of just 46g/km, but it's very difficult to come anywhere close to its mpg figure in real-world driving. Unless you have plenty of opportunities to plug the car in and charge the batteries, the car effectively becomes a normal petrol A3, and an expensive one at that. If regular charging won't be possible given how you'll use the car, a diesel A3 may prove cheaper overall. It can be driven solely on electricity for up to 29 miles.

The S3 and RS3 models will be the most expensive to buy, run and insure by far, but they’re aimed at enthusiasts that mostly won’t mind the extra costs. It’s also worth remembering that the A3 Convertible will cost more to buy and run, because it’s heavier than the hatch and saloon versions.

How much will it cost to insure?

The lowest insurance rating of any Audi A3 is group 16; the BMW 1 Series and Volkswagen Golf both start in lower groups. Audi insurance premiums are brought down, though, by the wealth of electronic safety systems on board. Depending on the engine and trim level, the A3 occupies groups 19-32. The RS3 model is in group 40, so it’s the most expensive to insure by far.