The IDC has posted its worldwide mobile phone tracker today, and in it they predict Windows Phone will ship 47 million units in 2014, climbing to 121.8 million units in 2018.

This would represent a 29.5% compound annual growth rate, and make Windows Phone the fastest growing mobile phone OS for the period.

The IDC also predicts both iOS and Android will lose market share, hitting 14.4 and 76% respectively, while Windows Phone will double its share to 7%.

Most of the growth will happen in the low-end of the market, with the average selling price of smartphones dropping from $335 in 2013 to drop to $260 by 2018.

The IDC also expects the whole smartphone market to slow down, with North America, Europe and Japan being particularly hit.

Do our readers think IDC is being optimistic or pessimistic? Let us know below.

Via PCMag.com