Marking all of your old messages as read can give you a fresh start and help you prioritize; however, Gmail's standard interface limits you to marking one page of messages at a time. Avoid wading through your messages page by page with Gmail's advanced search feature, which allows you to mark all of your unread messages at once.
1. Type "label:inbox is:unread" (without the quotes) into the Google search field at the top of the page, and then press "Enter." Gmail displays the first 20 unread messages in your inbox.
2. Click the "Down" arrow on the Select button and choose "All."
3. Click "Select All Conversations That Match the Results" in the message that appears near the top of the page. The message changes to indicate that all of the emails fitting your search description are selected.
4. Click the "More" button, select "Mark as Read," and then click "OK." Gmail marks all of your Inbox messages as read. This process may take several seconds or longer if you've accumulated hundreds of unread messages.
- You can use advanced search operators to select messages in other folders or unread messages in every folder. For example, to select all unread messages in your Important folder, type "label:important is:unread" into the search field. To select all unread messages in all folders, type "is:unread". See the "Advanced Search" link in the Resources section of this article for more search operators.