Parkers overall rating: 3.7 out of 5 3.7

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

Petrol engines 8.7 - 11.0 mpp
Diesel engines 10.0 - 11.4 mpp
Low figures relate to the least economical version; high to the most economical. Based on WLTP combined fuel economy for versions of this car made since September 2017 only, and typical current fuel or electricity costs.

Fuel economy

Petrol engines 40.9 - 51.4 mpg
Diesel engines 49.6 - 56.5 mpg
  • Fuel-efficient petrol engines 
  • Lots of fuel-saving technology
  • Including mild-hybrid systems

Despite the lack of full hybrid, PHEV and pure-electric versions of the 3, running costs are nevertheless impressively low.

The more popular petrol versions use a mild-hybrid system to give a small degree of electrical assistance to improve overall efficiency, resulting in claimed averages of 44.8-45.6mpg for the manuals and 42.2-43.5mpg for the automatics.

Diesel versions, without the mild-hybrid technology, perform even better, as you would expect. Manual models are quoted at 55.4-56.5mpg, with the auto versions being inferior at 49.6-50.4mpg. Note that the diesel-engined 3 disappeared from Mazda's price lists in October 2019.

Gor for the Skyactiv-X model and you can expect between 40.9 (an AWD automatic) and 51.4mpg (front-wheel drive manual). 

Mazda's Skyactiv package goes beyond engine efficiency, with unnecessary weight being stripped from all aspects of the car's structure. Being lighter means less stress on consumables such as brake components and tyres, meaning replacements could be required less frequently - we'll monitor that as the cars become older.

Fixed-price servicing packages are also available to help owners budget for what would otherwise be a major expense much more effectively.

In line with fuel efficiency figures, CO2 output is low given the lack of large-scale electrification of the powertrains. Nevertheless, no versions are close to dipping below 100g/km of CO2.

The Skyactiv-G petrol versions range from 117-128g/km of CO2, with the diesels performing similarly at 107-127g/km. The Skyactiv-X may well have the highest power output, but it also boasts some low CO2 figures, ranging from 100g/km to 125g/km. 

Is it reliable?

  • Traditionally a brand with a good reputation
  • Interior feels very well built 
  • Lots of new tech debuts, though

It's far too soon to know how reliable the latest generation of Mazda 3 will prove to be, but given that the majority of its mechanical components are familiar from other models in its stable, there shouldn't be much of a serious nature to be concerned about.

For now the biggest question mark remains around the Skyactiv-X engine that combines elements of how both petrol and diesel engines work. Engines on the test-bed will have already run for many thousands of hours, but how reliable they prove to be over the lifecycle of a car in the real world remains to be seen.

Ongoing running costs

Road tax (12 months) £150
Insurance group 15 - 23
How much is it to insure?