Microsoft sold 40 million licenses for Windows 8 in the program's launch month, Windows finance and marketing head Tami Reller told Reuters.
Sales of Windows 8 since its launch on Oct. 26 are higher than preliminary sales for Windows 7, which sold a little more than 60 million units during its first 10 weeks available in 2009. According to Reller, these numbers have been bolstered mostly by software upgrades rather than purchase of new Windows 8 devices.
"Windows 8 upgrade momentum is outpacing that of Windows 7," Reller said at an investor conference earlier.
The number also does not reflect 40 million unique Windows 8 users, but sales to PC manufacturers who in turn will sell new Windows 8 devices to companies, Reller says.
According to technology research firm and web analysis tool creator StatCounter, of the 1.5 billion or so personal computers running worldwide, around 15 million are currently running Windows 8.
Windows 8 upgrades for existing devices costs $40, while purchasing a new software package costs $70 and a new PC with the software pre-installed will run buyers upwards of a few hundred dollars.