Analysts expect Apple to announce sales of between 11.7 million and 19.5 million iPads for the quarter ending 31 December 2011 when it reveals its quarterly earnings report next week.

Fortune magazine polled 42 analysts - both professional and independent - in order to come up with an average estimate of how many iPads Apple sold in the final quarter of 2011.

The average figure was just under 14 million though estimates ranged from 11.7 million (Hendi Susanto of Gabelli & Co) and 19.47 million (Alexis Cabot of the Apple Finance Board). However, it's worth noting that Cabot's estimate is more than three million higher than any of the other analysts' predictions.

Also, like the predictions Fortune garnered for iPhone sales estimates earlier this month, the professionals had a slightly more pessimistic outlook than the independents, with the average pro prediction 13.5 million, with the average indie prediction 14.8 million.

Apple sold 11.12 million iPads in the quarter ending 30 September 2011, a year-on-year increase of 166 percent. It would only need to marginally beat that figure to hit 50 million iPad sales for the whole of calendar 2011.

Apple will reveal the figures in a call to anaylsts in just over a week when it issues its quarterly earnings report on Tuesday 24 January.