That's in terms of sales, not screen size. The firm says shipments of the phone-tablet hybrids will reach 318 million in 2015, more than tablet and portable PC shipments.
Emerging markets are still showing interest in new tablets, but that isn't enough to sustain IDC's prior forecast for this year.
Market researcher revises its prediction for global PC shipments in 2014, but it still expects a decline.
The number of personal computers worldwide is expected to drop 6 percent this year, according to a study published Tuesday.
Increasing demand for big-screen smartphones means tablet sales could be lower than expected, says research firm IDC.
Profits tumbled a stunning 74 percent in Samsung's mobile business in the third quarter, and tough times may continue. Here's what Samsung can do to turn things around.
Microsoft's mobile OS will surge, after a fashion, amid slower growth for the smartphone industry as a whole, predicts research firm IDC.
Increased focus on emerging markets has driven a 25 percent year-over-year increase in global shipments in the third quarter, according to IDC.
CEO John Chen says the company is committed to earning back your business with its next phone -- the BlackBerry Classic.
Apple will hold onto to a "value edge" in 2014, but Android's ecosystem is poised to make big gains, according to IDC.