How does Google Analytics classify new users versus returning users?
Essentially, a New User is a user that arrives on your site and does not already have the Google Analytics cookie present on their browser. They may have never been to the site before, have been there before but deleted the cookie, or visited the site before but on a different device or browser. Any of these situations would be considered a new user.
A Returning User would be a user that has the Google Analytics cookie present on their browser and Google Analytics identifies that they’ve been to the site before by the users Client ID, a dimension stored in the cookie
For more information, check out web analytic page.
Answered by: Paul Clemmer