Microsoft: Outlook.com now has over 400M accounts, 125M on mobile

Microsoft’s decision to get rid of Hotmail and replace it with Outlook.com appears to have paid off. With all Hotmail users now migrated to Outlook.com, Microsoft says it now has more than 400 million active accounts on the well-designed email service.

Outlook.com launched to positive reviews back in July 2012. A few months ago, Outlook.com exited preview with 60 million registered users. But the brunt of the work wasn’t done at that point because it still needed to move its many Hotmail users over to Outlook.com.

Microsoft said it migrated 150 petabytes of email in six weeks. The company writes in a blog post:

When Outlook.com came out of preview in February, it already had more than 60 million active accounts. However, Hotmail was still one of the most widely used services, with over 300 million active accounts. This made the magnitude of the process incredible, maybe even unprecedented. This meant communicating with hundreds of millions of people, upgrading all their mailboxes–equaling more than 150 million gigabytes of data–and making sure that every person’s mail, calendar, contacts, folders, and personal preferences were preserved in the upgrade. Of course, this had to be done with a live site experience that was handling billions of transactions a day. With your help, we were able to do all of that in just about 6 weeks. We’ve spent the last few weeks ensuring that everything was completed in line with our high quality expectations.

On the mobile front, things appear to be looking up for the email service. Microsoft said Outlook.com now has 125 million users that access it regularly on mobile devices.

One thing I find funny about this announcement is that Microsoft previously would not share its internal number of active Hotmail accounts. When I wrote about how Gmail had become the largest email service in the world with 425 million accounts back in June 2012, Microsoft refused to say how many active Hotmail accounts there were. Instead, it referred me to third-party numbers from comScore. (As did Yahoo.)

But now that Microsoft has internal metrics it likes and a service that works (and looks) better than Hotmail, it’s clearly time to boast.