In this post, we will show you how to check and increase the Outlook Mailbox size limit in MS Outlook and the new Outlook desktop app. Outlook provides a default mailbox storage limit depending on your account type. For most Outlook.com users, the default mailbox size is 15 GB, while Microsoft 365 subscribers enjoy a larger limit, ranging from 50 GB to 100 GB (Exchange Online) depending on the plan.
This capacity allows you to store a significant amount of emails and files. However, if your mailbox reaches its maximum capacity, you will not be able to send or receive emails until you free up space or increase the storage capacity of your account.
Check and Increase Outlook Mailbox size limit
In the following sections, we will show you how to check and increase your Outlook Mailbox size limit, so you can manage your mailbox size proactively, avoiding disruptions and ensuring a smooth email experience.
Check Mailbox size limit in Microsoft Outlook
Launch the MS Outlook on your desktop. Right-click your mailbox (in the left pane) and select Data File Properties.
In the Outlook Properties window, click the Folder Size button under the General tab.
A Folder Size window will appear, displaying details about the current size of your mailbox and the space used. The size of the mailbox and each subfolder will be displayed in kilobytes (KB).
To convert to megabytes (MB), move the decimal point three places to the left, and to convert to gigabytes (GB), move the decimal point six places to the left. For example, 4842 KB is roughly 4.8 MB.
Check Mailbox size limit in the new Outlook app
Open the new Outlook app on your desktop. Click the Settings (gear) icon in the top-right corner.
Navigate to Accounts > Storage in the Settings window.
Click Email storage to view detailed information about your mailbox size, including the total storage capacity and the amount currently being used by your Inbox, Drafts, and Sent Items.
Check Mailbox size limit in Outlook.com
A similar option is available in Outlook.com to check your mailbox size.
Open your web browser, go to Outlook.com, and sign in to your account. Click on the Settings icon located at the top right corner of the page.
In the Settings window, select General from the left sidebar, then click on Storage.
Here, you will see information about your mailbox size, including your total storage capacity and how much space you are currently using.
Increase Outlook Mailbox size limit
For Outlook.com, you may upgrade to a Microsoft 365 subscription, which increases your mailbox size from 15 GB to 50 GB or more, depending on the plan.
In the new Outlook desktop app and Microsoft Outlook for business, mailbox size is typically tied to your subscription plan or the settings of your organization’s Exchange Server. If you’re on a Microsoft 365 business plan, you can request an upgrade to a higher-tier plan that offers up to 100 GB of mailbox storage. Exchange Server users may request their IT administrator to adjust the mailbox size limit via the Exchange Admin Center.
Apart from increasing your mailbox size limit, you can also reduce its size by following some simple practices.
- Clean up Mailbox: For MS Outlook, use the built-in Mailbox Cleanup tool or compress Outlook Data Files to reduce the mailbox size. For Outlook.com, go to Settings > Storage. You’ll see a breakdown of how much space each folder uses, with the option to permanently delete all items or those older than 3, 6, or 12 months to free up space.
- Empty the ‘Deleted Items’ folder: Regularly empty your Deleted Items folder to remove emails that are no longer needed permanently. This ensures that they don’t continue taking up valuable storage space.
- Empty the ‘Junk Email’ folder: Periodically clear out your Junk Email folder to get rid of spam or unwanted messages that can accumulate and consume storage over time.
- Sweep unwanted emails: Use the Sweep feature to delete or move unwanted emails from specific senders quickly. This will help manage recurring emails and prevent unnecessary buildup in your inbox.
- Archive older items: Outlook automatically archives items at regular intervals, but you can also archive them manually. This removes them from your active mailbox whenever you want, while still keeping them accessible for future reference.
- Save attachments outside your mailbox: To avoid filling up your mailbox with large files, save email attachments to OneDrive or another cloud storage service and then remove them from the emails.
By following the above practices regularly, you can efficiently manage the size of your Outlook Mailbox, keeping it lean and organized.
Read: Outlook Quota Exceeded, The account is above quota limits.
How do I increase email size limit in Outlook?
If you have administrator access, you can modify the registry to increase the attachment size limit. Open Registry Editor and navigate to HKEY_CURRENT_USER\Software\Microsoft\Office\<version>\Outlook\Preferences.
Right-click on the right pane and create a new DWORD (32-bit) Value called MaxAttachmentSize. Set the value in KB (e.g., for 25 MB, set it to 25600).
Restart Outlook for changes to take effect. If you’re using a corporate account, contact your IT administrator for assistance in increasing the email size limit.
How do I fix Outlook storage limit?
If your mailbox is nearing its size limit, consider upgrading to a Microsoft 365 subscription for increased storage capacity. Additionally, regularly archiving old emails to a separate PST file, deleting unnecessary items, and using cloud storage services like OneDrive for large attachments can help manage your current mailbox size efficiently.
Read Next: Outlook not sending emails in Windows, With or Without attachments.
