The Android mobile operating system (OS) will reach one billion users across all devices this year– increasing its lead over Windows and Apple’s iOS to outsell each of those platforms by as much as three times, according to research firm Gartner.

Makers of mobile PCs, tablets, ultramobiles and mobile phones are projected to ship a total 2.5 billion devices in 2014, a 7.6 percent increase from 2013. Mobile phones are expected to dominate, with 1.9 billion shipped in 2014, a five percent increase from 2013 (see first table below).  But ultramobiles, which include tablets, hybrids and clamshells–will take over the wheel as the main driver of growth–growing at 54 percent.

“Mobile phones are a must have and will continue to grow but at a slower pace, with [growth] moving to mid-end basic products,” says Ranjit Atwal, research director at Gartner. “Meanwhile users continue to move away from traditional notebooks and desk-based PC, while the greater flexibility of tablets, hybrids and lighter notebooks address users’ increasingly different demands.”

In 2014, the worldwide tablet market will grow 47 percent with lower average selling prices attracting new users, says Atwal.

According to a recent consumer study that Gartner carried out in the third quarter of 2013 across Brazil, China, France, Germany, Italy, the U.K., the U.S. and Japan, over two-thirds of people used tablets outside the home for activities such as a vacation or concert. “This is a similar pattern to that of smartphones as smaller form factors are driving more portability outside the home,” says Atwal.

Shipments of traditional PCs are forecast to total 278 million units worldwide in 2014, a seven percent decline from 2013.  Driven by an uptake in Windows ultramobiles, the PC market is estimated to remain flat in 2014 (0.2 percent), after a decline of 9.9 percent in 2013.  The Gartner survey showed that less than eight per cent of users would replace their laptop with a tablet, but almost twice that many said they would transfer to an ultrabook.

In the OS market, Android continues to be the OS of choice across all devices (see Table 2). Gartner estimates that Android will reach 1.1 billion users in 2014, a 26 percent increase from 2013.  Because of its low cost compared to other mobile platforms, Android has been especially popular in emerging markets, and by 2017, over 75 percent of Android sales will come from emerging market countries.

“There is no doubt that there is a volume versus value equation, with Android users also purchasing lower-cost devices compared to Apple users,” says Gartner principal analyst Annette Zimmerman. “Android holds the largest number of installed-base devices, with 1.9 billion in use in 2014, compared with 682 million iOS/Mac OS installed-base devices.”

Gartner’s market forecast data is detailed in “Forecast: PCs, Ultramobiles, and Mobile Phones, Worldwide, 2010-2017, 4Q13 Update,” which is available on the Gartner website.