Google doesn't officially disclose the number of units sold and in the case of the Pixel smartphones that's particularly irksome. However the company's Play Store gives us a pretty accurate estimate of how many Pixel and Pixel XL phones Google has sold. See Google's Play Store gives a range number for app installs and in the case of the Pixel Launcher app that number just passed from the threshold from the 500,000 - 1,000,000 to 1,000,000-5,000,000 meaning that Google has sold around 1 million Pixel smartphones since their launch some 8 months ago. The Pixel Launcher is exclusive...
Source: http://www.gsmarena.com/google_has_sold_around_1_million_pixel_smartphones-news-25610.php