Software & Apps MS Office How to Check Your Outlook Folders & Sizes Reduce your Outlook folder sizes by finding the largest emails By Heinz Tschabitscher Writer A former freelance contributor who has reviewed hundreds of email programs and services since 1997. our editorial process Heinz Tschabitscher Updated January 31, 2020 MS Office Outlook Word Excel Powerpoint Tweet Share Email Has handling email in Outlook become slow and unwieldy, is your hard disk shrinking, or are you about to reach your Inbox size limit and you suspect the emails with attachments might be involved? Outlook comes with a tool that shows how much space each folder occupies. Find out how big your email folders have grown in Outlook and take action if they are too big. Instructions in this article apply to Outlook 2019, 2016, 2013, 2007; and Outlook for Office 365. Check Your Outlook Folders' Sizes To see the size of your folders in Outlook: Right-click the folder where you want to check the size and select Data File Properties. In Outlook 2019, select Properties. In the Properties dialog box, select Folder Size. The Folder Size dialog box shows the size of the folder in kilobytes, as well as a breakdown of all of the subfolder sizes. By checking the size of each folder and subfolder, you can identify which account is using up the most space, as well as the subfolders that may contain files that are too large. Check Your Folders' Sizes in Outlook 2007 To see the size of your Outlook 2007 folders: Select Tools > Mailbox Cleanup.Select View Mailbox Size.Select Close (two times) to close the mailbox size view again. Reduce the Size of an Outlook File by Archiving Mail Archiving old or less frequently accessed messages is an easy way to keep all your Outlook folder and files' sizes manageable. Outlook can even do the archiving automatically. Find the Biggest Emails in Your Outlook Folders To have Outlook gather all the biggest emails found across all your folders: Select the Search Current Mailbox text box. Or, press Ctrl+E. Go to the Search tab. In the Options group, select Search Tools > Advanced Find. In the Advanced Find dialog box, select the Look dropdown arrow and choose Messages. To search more folders than the inbox (or whichever folder is currently open in Outlook's main window), select Browse. Select the check box next to the folders you want to search and select the Search subfolders check box. Select OK. In the Advanced Find dialog box, go to the More Choices tab. Select the Size (kilobytes) dropdown arrow, choose greater than, then enter a size (such as 5000 for folders greater the 5 MB). Select Find Now. Double-click a message to open it and deal with it as you see fit. Or, select Delete in the search results to delete any message right away.