Parkers overall rating: 4 out of 5 4.0

Miles per pound (mpp) Miles per pound (mpp)

Reliable fuel consumption data for comparison purposes is not available for this model.

Fuel economy

A more stringent standard for fuel economy (WLTP) was introduced from September 2017, and this model was not required to undergo that test. Its fuel economy measured under the previous test system was 50 - 74 mpg. However these figures are less likely to be achievable in real world driving and so should never be compared to another car's mpg which was measured under the newer, more realistic WLTP system.

The best Mazda 3 Fastback to pick if fuel economy is a concern would be equipped with the 1.5-litre SkyActiv-D diesel engine. Its claimed average of 74.3mpg is probably a little optimistic during real-world driving, but over 50mpg is easily possible. This will be the company car driver favourite too, since its 99g/km CO2 output makes for cheap benefit-in-kind tax.

If you’re doing shorter journeys and lower overall mileages then investigate one of the excellent SkyActiv-G petrol engines, though. A combined figure of 55.3mpg is on offer with the 2-litre manual, so not quite as impressive as the diesel, but it’s cheaper to buy and better to drive.

The 1.5 SkyActiv-D diesel engine is your best bet in the Mazda 3 Fastback line-up, emitting 99g/km of CO2. Adding an automatic gearbox to the petrol 2-litre makes for the dirtiest one, but even that only emits 128g/km – hardly a game-changing amount.

There’s little to worry about reliability-wise with the Mazda 3 Fastback, with all the mechanical components delivering bulletproof service across a range of the firm’s other models.

Not only that, the interior feels as though it’ll stand the test of time, too, although we do have niggling doubts about whether the first cabin rattles will emerge from the flimsy lid on the central armrest cubby.

Ongoing running costs

Road tax (12 months) £0 - £165
See tax rates for all versions
Insurance group 13 - 24
How much is it to insure?