“Is my mailbox almost full? I need to check my storage limit.”
Have you ever received that dreaded notification warning about your mailbox approaching its size limit? Or perhaps you’re experiencing slow performance in Outlook and suspect your mailbox size might be the culprit. For many business professionals, monitoring mailbox storage is essential to ensure uninterrupted communication flow. Understanding how much space your emails occupy and where that storage is being used can help you maintain an efficient workflow in Microsoft 365.
Find the size of my mailbox before it causes problems 🙂
Organizations typically assign specific storage quotas to each user’s mailbox in Microsoft 365. When you approach or exceed these limits, you might experience issues like those seen when trying to speed up Outlook’s slow performance. Monitoring your mailbox size proactively allows you to manage your storage effectively, archive older items, and delete unnecessary content before problems arise.
This tutorial will show you multiple methods to check your mailbox size in Outlook desktop client, Outlook on the web (OWA), and through other Microsoft 365 tools.
View mailbox size in Office 365 – solution options
We’ll cover several methods to check your mailbox size depending on your preferred access method and available permissions. The techniques range from simple user-level checks within the Outlook interface to more detailed administrative views. These approaches work across different versions of Outlook desktop clients and Outlook on the web. No special tools or add-ins are required, just your standard Microsoft 365 subscription and appropriate access permissions.
How to show email size in Outlook desktop application
- Check folder sizes directly in Outlook desktop by right-clicking on your mailbox name in the folder pane and selecting “Data File Properties” or “Properties” depending on your account type, then click the “Folder Size” button to display a breakdown of storage used by each folder.
- View the total mailbox size in Outlook desktop by navigating to the File tab, clicking on the “Info” section, and looking for the “Mailbox Cleanup” tool, which displays your current usage and quota information in a convenient dashboard format.
- Examine specific folder storage consumption by right-clicking any folder (like Inbox, Sent Items, or custom folders), selecting “Properties,” and then clicking the “Folder Size” button to see how much space that particular folder and its subfolders are consuming.
- Generate a mailbox size report by selecting multiple folders while holding the Ctrl key, right-clicking, choosing “Properties,” and then “Folder Size” to get a comprehensive view of your storage distribution across different message categories.
- You can also enable the folder size column in Outlook’s view by right-clicking the column headers in the folder pane, selecting “View Settings,” clicking “Columns,” and adding the “Size” column to display folder sizes directly in your navigation pane for quick reference.
Find size of Outlook mailbox through Outlook on the web (OWA)
- Access mailbox size information in OWA by clicking on the gear icon (Settings) in the top-right corner, selecting “View all Outlook settings,” navigating to “General,” and then clicking on “Storage” to see your current usage and mailbox limit.
- Check individual folder sizes in OWA by right-clicking on any folder, selecting “Properties,” and reviewing the size information, which helps identify which areas of your mailbox are consuming the most space.
- View attachment storage usage in OWA by navigating to Settings > General > Storage, where you’ll find a breakdown of how much space is being used by attachments versus regular email content, giving you targeted insights for cleanup efforts.
- Review deleted items retention space usage by checking the storage statistics screen, which typically shows separate allocations for your recoverable items folder, helping you understand if purging deleted items might free up significant space.
Office 365 mailbox size check troubleshooting
- If you don’t see the Folder Size button in properties, you might need to check if you’re using a cached Exchange mode account – in this case, switch to the advanced properties dialog by holding Ctrl while clicking Properties on the folder, or temporarily switch to online mode in account settings.
- If storage information appears inconsistent between different views, remember that synchronization delays between the local cache and server can cause temporary discrepancies. You may need to auto refresh your Outlook inbox to see the most current server-side information.
- If you have access to multiple mailboxes or shared mailboxes, be aware that the default view only shows your primary mailbox size – to check other mailboxes, you need to right-click specifically on that mailbox name in the folder pane and follow the same steps for each separate mailbox.
Pro tip: Regular maintenance of your mailbox not only helps you stay under quota limits but also improves Outlook performance. Consider setting a quarterly calendar reminder to check your mailbox size and perform cleanup activities.