More than 400 million ‘phablets’ will ship in 2019, a five-fold increase over the 138 million expected to be shipped in 2015, according to a study from Juniper Research.

And while the iPhone 6 Plus has boosted the profile of such devices (Samsung’s Galaxy Note line also being clearly premium), it is “budget” devices that will drive the 5.5-inch to 6.9-inch product category into the mainstream, claims Juniper.

In addition, with steady increases in smartphone screen size, many flagship smartphones are likely to be phablets “by default” within the next two or three years, Juniper said.

This comes as owners are increasingly using smartphones as media consumption and gaming devices, which offer richer experiences through a larger screen. Some vendors will also offer productivity software as standard with some devices.

But the growth of phablets will impact the market for smaller-screen tablets. This will slow adoption of the larger device in markets where customers “already do most computing on smartphones”, such as China, the research firm said.