Depending on which engine and transmission you choose, the fuel consumption of your A3 can be as poor as 39.8mpg (almost on par with the entry-level petrol Porsche Panamera). Or it can be as good as 74.3mpg (and most Smart ForTwos don’t do that well).
In reality these figures bear little relation to the truth, but don’t blame Audi but the entirely unrealistic way in which the EU requires it to calculate them.
What can be said is that relative to its key rivals, the A3 is a frugal car making it cheap to run either as a private or company car. Experience with the core 2-litre TDI suggests owners should routinely expect to return over 50mpg which, given the performance and sophistication of the product is a magnificent result.
However it is to be remembered that Audi offers a mere three year warranty as standard, which can only be extended to four or five years (and still with limited mileages) for hefty additional fees.
Any Hyundai will give you five years for free and with no mileage cap.