Global sales of "smart devices," which include smartphones and tablets, will hit 821 million worldwide this year and 1.2 billion in 2013, a research firm said Tuesday.

Gartner Inc. said these devices are gaining strong momentum, as many consumers opt to use them instead of personal computers.

"For most businesses, smartphones and tablets will not entirely replace PCs, but the ubiquity of smartphones and the increasing popularity of tablets are changing the way businesses look at their device strategies and the way consumers embrace devices," said Carolina Milanesi, research vice president at Gartner.

By 2016, Milanesi said, "two-thirds of the mobile workforce will own a smartphone, and 40 percent of the workforce will be mobile."

She said tablets will be a key to mobility for workers, with 13 million tablets used for business this year, rising to 53 million by 2016.

Gartner estimates that 56 percent of smartphones purchased by businesses in North America and Europe will be Android devices in 2016, up from 34 percent in 2012.

"Today the wide range of brands and price points that the Android ecosystem is offering is winning over users. While Apple remains the heartbeat by which the market moves, Google has rapidly become its archrival," she said.

A separate survey by research firm IDC last week found three out of four smartphones shipped worldwide used the Google-backed mobile platform, even though Apple's iOS devices are growing.

Milanesi said BlackBerry maker Research in Motion, long the dominant force in smartphones, "has a huge challenge ahead in regaining its key presence in the enterprise."

She said that in the business market, Windows 8 will take the number three position in the tablet market behind Apple and Android by 2016, with interest coming more from businesses than consumers.