Discerning these numbers is a tad tricky since there are three powertrain combinations for each 2019 Mazda3 bodystyle, and they all get slightly different fuel economy. We've listed the different combinations in a chart below:
There are a few key takeaways, the first being that the sedan is always the most efficient version of the Mazda3, likely because of better aerodynamics compared to the hatchback. Second, all-wheel drive will cost you fuel economy due to the extra weight of the axles and differential, and the added drag on the engine. Third, the most efficient versions of each body have the same fuel economy numbers as the outgoing Mazda3. The manual transmission-equipped Mazda3 has actually improved fuel economy over the old version by 2 mpg on the highway, and 1 in combined driving.
Also worth noting is that only one trim level of the sedan is available with cylinder deactivation and front-wheel drive, and that's the top-level Premium trim. Opting for all-wheel drive on any trim or body style will come with an engine with cylinder deactivation. The hatchback is also the only Mazda3 available with a manual transmission, and it's only offered on the front-drive version.