Now it’s official: the iPad is the top selling tech gadget ever. This news comes from Colin McGranahan, of Bernstein Research, in a posting at InformationWeek. He concludes that 8.5 million units have been sold to date, which gives the iPad the crown as the best-selling tech gadget in history.

According to InformationWeek:

The iPad smashed industry records earlier this year when it sold 3 million units in its first 80 days on the market. Third quarter sales were in the range of 4.5 million units, and overall it’s estimated that Apple has shipped about 8.5 million iPads to date worldwide.

Not only is the iPad an amazing success, but now it looks like it is beginning to eat into PC sales too. According to TUAW, a recent research study by NPD found that 13% of iPad users would have purchased a PC if they hadn’t been able to buy an iPad.

The iPad was released in April and was originally only available through Apple and at select Best Buy stores. Now, Apple’s device is available at Target and all Best Buy stores. Plus, with the holiday season starting, rumors continue to fly that the iPad will soon be available at Walmart too. Soon that 8.5 million units number could look small.