Great news for Gmail users, now Access Two Gmail Accounts at once in the Same Browser. Yes now you can access your two different Gmail accounts at the same time in the same browser. I have a couple different Gmail addresses that I use for different purposes. Historically, Google Accounts – including Gmail accounts — have only let people access one account at a time per browser, so using both accounts has been a bit inconvenient. I’ve either had to sign out and sign back in, use a second browser for my second account, or use a Chrome incognito window. And I'm not alone; lots of people have asked this for a better way to use multiple accounts at once in the same browser.
Now, you can visit google.com/accounts and click the link next to "Multiple sign-in." Just follow the steps given below and you will have both your Gmail accounts ready to go with.
After you sign into your first account, you can sign in with up to two additional accounts from the new accounts menu in the upper right hand corner of Gmail, then easily toggle back and forth between them.
You can even open multiple Gmail tabs — one for each of your accounts.
You can use multiple sign-in with the following desktop versions of these Google products:
Other Google products and the mobile versions of the above products do not support the use of multiple accounts in the same web browser. Instead, they default to the first account that you signed in to from your current browser.
Please keep in mind that this is a feature for advanced users, and there are a couple things to watch out for:
1) Not all Google services support multiple account sign-in yet. For the services that don't support it (like Blogger and Picasa Web Albums), you'll be defaulted to the first account you signed in with during that browser session. So if you click a link from Gmail to Blogger, for example, you'll be logged into Blogger with the first account you signed in with, even if you clicked the link to Blogger from your second Gmail account.
2) We’re still working on making Gmail and Calendar work offline with multiple sign-in. If you rely on offline access, you probably don't want to enable this feature quite yet.
3) Multiple account sign-in only works on desktop browsers for now, so if you use Gmail on your phone's browser you won't see this option yet.
Tip: Always check your address (at top right) to make sure you’re using the account you want.