Forecast: Tablet shipments to outpace PCs by 2015

• More people use tablets instead of PCs
• Tablets with smaller screens are seen grabbing bigger share

The stampede to tablets and other mobile devices is picking up speed and noise.

Tablet shipments will surpass laptops this year and are forecast to outpace the combined PC market by 2015, says a report from research firm IDC.

The surging tablet market will continue to soar this year, with shipments expected to rise 58.7% compared with the same time last year, IDC forecast on Tuesday. Tablet shipments will reach 229.3 million worldwide, vs. 144.5 million last year.

The migration to tablets is a continuation of an "operating system shift" away from traditional desktop PCs to first Apple's iOS (on iPad and iPhone) and now Android devices such as Samsung and HTC, says Charles King, principal analyst at market researcher Pund-IT.

Indeed, this year marks the transition from a PC world to a mobile one, says Bob Tinker, CEO of MobileIron, a mobile management and security company. "Tablets and smartphones reorganized the consumer-electronics market," he says. "That is now extending to the enterprise market."

IDC analyst Ryan Reith added that the shift to tablets "marks a significant change in consumer attitudes about computer devices and the applications and ecosystems that power them."

"For many consumers, a tablet is a simple and elegant solution for core-use cases that were previously addressed by the PC," Reith says.

The rise in tablet use will be fueled by smaller devices with screens smaller than 8 inches. In 2011, tablets with screens between 8 and 11 inches — such as Apple's popular iPad — commanded a 73% market share. By 2017, tablets in that range will dip to 37%.

Meanwhile, tablets such as iPad Minis and Amazon Kindles with screens smaller than 8 inches will command 57% market share by 2017, up from 27% just two years ago.

Declining prices are accelerating the trend. The average price of a tablet this year will drop to $381 from $423. That is about half the price for the average PC ($635), IDC says.

The IDC forecast is another sign of the PC market's struggles. In April, IDC reported PC shipments fell by the largest margin ever — 14% in the first quarter.

"The PC is the equivalent of the land-line phone," analyst King says. "What do you need it for?"