As expected from a previous leak earlier this month, Google just announced on its official Gmail blog that it’s rolling out a brand new UI for Gmail on both the web and mobile that brings a new Categories based UI for easier organization of emails. The screenshots below line up with the images that we posted last week showing new customizable Categories that users can assign to manage emails according to content. For example: ‘Social’ for emails related to social networks, ‘Promotions’ for promotional material, ‘Notifications’ for reservations, bills, etc, and ‘Forums’ for mailing lists and forums.

The update is not only rolling out to desktop users, but also to iPhone and iPad and mobile devices running Android 4.0 and up. On the mobile apps, users will first see their “Primary” inbox and can switch to other categories using the side navigation bar. Google says the new inbox is rolling out in the next few weeks but users will be able to try it sooner with a new “Configure inbox” option in Settings.

Google noted that users that aren’t liking the new organization features will be able to “simply switch off all optional tabs to go back to classic view, or switch to any of your other favorite inbox types.