Counting tablet PCs as personal computers, Apple is about to overtake Hewlett-Packard and become the world’s top personal computer vendor. All should be known soon when Apple reveals holiday quarter earnings in a conference call with analysts scheduled for Tuesday, Jan. 24.

HP CEO Meg Whitman was first to admit that such a turn of event neither would nor be entirely unsurprising given Apple’s lead in the post-PC world. Whitman said back in November, “It’s possible if you integrate tablets.” Fortune’s Philip Elmer-DeWitt wrote that, based on a poll of 42 analysts, iPad sales could hit the 14 million mark, a notable increase over the 11.12 million iPads sold during the September quarter.

Fortune’s estimates range from 11.7 million (Hendi Susanto of Gabelli & Co) to 19.47 million iPads (Alexis Cabot of the Apple Finance Board). According to research firm Gartner, HP shipped 14.7 million PCs in the last quarter, down 16 percent from a year ago.

Now, Apple in this last quarter cleared 4.89 million Macs, and its holiday sales are estimated to exceed 5 million units. Combined, iPad and Mac will have sold over 20 million units during the holiday quarter, enough to give the Cupertino, Calif.-based technology powerhouse a few million units lead over HP, the world’s leading computer vendor.

Estimated unit sales translate into a 17.6-percent market share for Apple versus 13 percent for HP, representing a landmark achievement by any measure. Again, that’s assuming tablets are counted as personal computers. As noted by Asymco’s Horace Dediu, Apple has never held the top spot. Its Apple II system peaked at 15.8 -percent share in 1984 and the Mac peaked at 12 percent in 1992. Interesting that Lenovo CEO praised Apple last week, saying about Android on tablets that “We still need to learn something, we still need to improve something”.

Apple is largely expected to blow analysts’ estimates out of the water. Localytics saw record-setting holiday sales, reporting 12 times the amount of activations of iOS devices on Christmas Day. We also know that carrier Verizon Wireless activated 4.2 millions iPhones during the holiday quarter, doubling the previous quarter. Morgan Stanley also said some nice words about iOS devices, expecting Apple to have sold nearly a quarter billion iPhones and iPads during 2011.  Morgan Stanley’s Katy Huberty even wrote in a note to clients that United States consumers could buy more iPhones in the first calendar quarter of 2012 than during the holiday quarter of 2010. With strong iPhone 4S sales stemming from new U.S. carriers, including the fastest rollout and the widest price matrix ever ($0 iPhone 3GS, $99 iPhone 4 8GB and various iPhone 4S price tiers), Apple is expected to exceed Wall Street’s consensus again.

Last quarter was a discrepancy after Apple surprised Wall Street with a bit lower-than-expected earnings. Those thinking about buying either puts or calls just before Apple’s Q4 earnings report is released should be aware that such a strategy is not necessarily a prudent one. Some more estimates by individual analysts and bloggers can be read here. Fortune also has a nice outlook on holiday-quarter sales estimates for iPhone, ranging anywhere between 25 million and 35 million units.

FTC: We use income earning auto affiliate links. More.

Check out 9to5Mac on YouTube for more Apple news:

You’re reading 9to5Mac — experts who break news about Apple and its surrounding ecosystem, day after day. Be sure to check out our homepage for all the latest news, and follow 9to5Mac on Twitter, Facebook, and LinkedIn to stay in the loop. Don’t know where to start? Check out our exclusive stories, reviews, how-tos, and subscribe to our YouTube channel

About the Author