In-depth reviews

Audi A3 review - MPG, CO2 and running costs

The Audi A3 has strong, efficient petrol and diesel engines, while plug-in hybrid power is an efficient option

Overall Auto Express Rating

4.0 out of 5

MPG, CO2 and running costs Rating

3.8 out of 5

£27,565 to £49,505
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Audi has progressively developed the A3 range to now include petrol, diesel and plug-in hybrid engines, delivering competitive running costs and low emissions.

The 30 TFSI petrol unit, with a six-speed manual ‘box, returns an impressive maximum of 51.4mpg and emits 124g/km of CO2, while the 35 TFSI manages a creditable 47.9mpg and CO2 emissions of 133g/km.

The 35 TFSI seven-speed S tronic auto is actually more efficient than the manual version, delivering 49.6mpg and 129g/km of CO2. Upgrading to the 40 TFSI is no longer an option as Audi has removed it from the A3 price list, but if you do secure a used example you'll still see overall economy at a reasonable 39.2mpg, with CO2 emissions of 164g/km.

Company car drivers will be attracted by the A3 TFSI e models which offer lower CO2 emissions (around 26g/km) and a lower benefit-in-kind tax rating. It's possible to travel around 37 miles on electric power alone, so if you keep the battery regularly topped up and mostly cover shorter journeys, you could really save on bills.

If you’re looking for the best return from a tank of fuel, the 35 TDI offers a claimed 61.4mpg and 120g/km of CO2. Both the 30 TDI and 40 TDI models were discontinued in early 2022. The former offered a maximum of 64.2mpg and just 115g/km of CO2, while the latter returned 50.4mpg with 147g/km.

Buyers looking towards the performance S3 and RS 3 models, probably won't be overly concerned with overall efficiency, although the S3 still manages a decent 34.9mpg on the combined cycle. The more powerful RS 3 predictably fares a little worse, returning an average of 31.4mpg.

Insurance groups

The petrol-engined A3 versions sit in insurance groups 14-29, with diesel cars similarly graded, except that they start from group 16 due in part to not being offered with the entry Technik trim level. By comparison, a 107bhp Mercedes A 160 petrol in AMG Line trim is in group 15, while an A 180 diesel with 114bhp and the same AMG Line equipment level starts from group 18. The standalone S3 and RS 3 models are in group 31 and 35 respectively.


Data suggests that the A3 will retain around 55 per cent of its original value over three years and 36,000 miles, with the BMW 1 Series performing similarly and the Mercedes A-Class a touch behind on 53 per cent over the same period.

Which Is Best


  • Name
    30 TFSI Technik 5dr
  • Gearbox type
  • Price

Most Economical

  • Name
    35 TDI Technik 5dr
  • Gearbox type
  • Price


  • Name
    S3 TFSI Quattro 5dr S Tronic
  • Gearbox type
  • Price
Executive editor

Paul was employed across automotive agency and manufacturer-side sectors before joining Auto Express in 2020 as our online reviews editor. After a brief sojourn at a national UK newspaper, Paul returned as executive editor where he now works closely with our commercial partners.

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