The total shipment stood at 2.3 billion units in 2013 and is poised to grow to 2.62 billion units by 2015, Gartner said in a statement.
Also, operating system (OS) Android, which powers multitude of gadgets like smartphones, tablets and smartwatches, is on pace to surpass one billion users across all devices in 2014, Garter said in a statement.
"The device market continues to evolve, with buyers deciding which combination of devices is required to meet wants and needs," Gartner Research Director Ranjit Atwal said.
"Mobile phones are a must have and will continue to grow but at a slower pace, with opportunities moving away from the top-end premium devices to mid-end products," Atwal said.
Also Read
PC sales (desktops and notebooks), on the other hand, are expected to decline seven per cent to 277.9 million units this year from 299.3 million units. PC shipments is forecast to stand at 268.4 million units in 2015.
"Users continue to move away from the traditional PC (notebooks and desk-based) as it becomes more of a shared content creation tool, while the greater flexibility of tablets, hybrids and lighter notebooks address users' increasingly different demands," he said.
"Complimentary smaller tablets will take over from the larger tablet form factors, providing the added mobility that consumers desire at a lower cost and will compete with hybrids for consumer attention," Atwal said.
In 2014, the worldwide tablet market is forecast to grow 47 per cent with lower average selling prices attracting new users as consumers continue to buy tablets as an additional device that they carry everywhere.
In the OS market, Android continues to be the operating system of choice across devices. By 2017, over 75 per cent of Android volumes are seen coming from emerging markets.
"There is no doubt that there is a volume versus value equation, with Android users also purchasing lower-cost devices compared to Apple users," Gartner Principal Analyst Annette Zimmerman said.
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, she added.
Windows-powered device sales is expected to be 359.8 million, while that of of iOS and BlackBerry is forecast to be 344.2 million and 15.4 million, respectively.