Increase Mailbox Size in Microsoft 365 Exchange Online – A Complete Guides

Reasons for Increasing Mailbox Size in Microsoft 365

Email is still one of the main ways people and businesses stay in touch. But when your mailbox starts getting full, things can quickly go wrong. If you are using Microsoft 365 and reach the storage limit, it can stop your email from working correctly. That’s why it is important to know why increasing your mailbox size is not just useful. It is sometimes the only way to keep everything running smoothly.

• If you get a lot of emails every day, like updates, replies, and alerts, your inbox can fill up quickly. It is even more common in busy roles like sales, customer service, or project work.
• Emails that include PDFs, spreadsheets, presentations, or images take up far more space than plain text. The more of these you receive, the faster your mailbox fills up.
• Some users prefer to keep a complete email history when it involves contracts, client conversations, or sensitive communications. Deleting isn’t always a safe option.
• Microsoft allows archiving, but if you have been storing emails for years, even your archive mailbox may start to run low on space if auto-expanding isn’t turned on.
• A full mailbox can cause sync delays or even failures in Outlook. Hence, it becomes hard to access or send emails from the desktop app.

All of these are clear signs it’s time to increase your mailbox size. Doing it early helps avoid issues and keeps your email running smoothly.

Now, let’s talk about what can go wrong if your mailbox hits its limit:

• You won’t be able to send or receive any new emails, which can instantly interrupt your workflow.
• Along with that, you could miss out on important messages without even knowing it.
• The Outlook desktop app may stop syncing properly.
• And if you are forced to delete emails in a hurry just to free up server space, you could accidentally lose something important.

That’s why managing your mailbox size before it becomes a problem is so important. It keeps your work running smoothly without interruptions or storage worries.

Default Mailbox Size Limits in Microsoft 365 Plans

Microsoft 365 offers different mailbox size limits depending on the O365 subscription plan you’re using. These limits are set by default. It can impact how many emails you can store before you run into space issues.

Note: Archive mailboxes are off by default. You can turn them on using the Exchange Admin Center or PowerShell. Once enabled, they auto-expand up to 1.5 TB. If your primary mailbox is full, you would not be able to send or receive emails until you archive or add more space.

How to Monitor Your Mailbox Size in Microsoft 365 Outlook 

Before your inbox runs out of space and starts causing trouble, it is better to keep an eye on how much storage you have used. Now, look at how you can easily monitor your mailbox size in Microsoft 365 Outlook.

• First, open Outlook Online in your preferred web browser.
• Next, sign in using your Microsoft 365 account credentials.
• Then, click the Settings (⚙️) icon at the top-right corner of the screen.
• After that, scroll down and click on View all Outlook settings.
• Now, go to the General tab and select Storage from the list.
• Finally, review the storage diagram to see how much space you’ve used and which folders are using the most.

Now, View Your Existing Office 365 Mailbox Usage

• First, log in to your Microsoft 365 admin center.
• Then, click on the Reports section from the left menu.
• Next, go to Usage to open the Microsoft 365 usage page.
• After that, under Email activity, click View More.
• Finally, select Exchange >> Mailbox usage to view your storage report.

Now, you can navigate through the best options to help you keep your inbox running smoothly.

Simple Ways to Increase Mailbox Size in Microsoft 365 Exchange Online

We are here with helpful solutions to upgrade the mailbox size in Microsoft 365. There are several simple ways to increase your mailbox size in Microsoft 365 Exchange Online. Once you have the details, you can use the methods below to increase your Office 365 mailbox size up to 100 GB.

Method 01: Upgrade to a Higher Microsoft 365 Plan

If you’re on a lower-tier plan like Business Basic or Business Standard, your mailbox limit is 50 GB. Upgrading to a plan like Microsoft 365 E3 or E5 gives you 100 GB of primary mailbox storage.

1. To initiate, log in to the Microsoft 365 Admin Center.
2. After that, navigate to Billing and tap Your Products button.
3. Now, hit on the Upgrade next to your current plan.
4. Select a plan like E3 or E5 and follow the on-screen instructions.
5. After upgrading, your mailbox will automatically be upgraded to a 100 GB limit.

Note: You must be a global or billing admin to upgrade your plan to increase mailbox size in Microsoft 365 Exchange Online.

Method 02: Enable Archive Mailbox

An archive mailbox acts like an extra storage location. It’s separate from your primary inbox and starts with 100 GB of space.

• Go to the Microsoft 365 Compliance Center:
• Click Data Lifecycle Management >> Archive.
• Now, you’ll see a list of user mailboxes.
• Select the user and click Enable next to Archive Mailbox.
• The archive mailbox will appear as a second mailbox in Outlook or Outlook Web.

Tip: You can move old or large emails here manually or with retention policies.

Method 03: Increase Office 365 Mailbox Size via PowerShell

Using PowerShell, Microsoft 365 admins can increase the mailbox size for users who have E3 or E5 (Plan 2) licenses. This method lets you set a custom mailbox size up to 100 GB for the main mailbox.

• You need to be a global admin or an Exchange Online admin.
• The user’s account must be using Exchange Online Plan 2, like Microsoft 365 E3 or E5.
• This method won’t work for Business Basic or Standard plans because their mailbox size is limited to 50 GB.

Steps to Fix Exchange Online archive mailbox size Using PowerShell

• Install the Exchange Online PowerShell Module. You only need to do this once per system.
• Install-Module -Name ExchangeOnlineManagement
• Enter these command to connect to Exchange Online PowerShell

• You can replace admin@yourdomain.com with your global admin email address.
• Now, users can check Current Quota Settings for the Mailbox.

• Also, you can manually set higher limits (up to 100 GB for Plan 2 mailboxes):

Method 04: Backup and Free Up Server Space of your Exchange Online Archive Mailbox

To free up space in your Exchange Online archive mailbox without losing important data, you can use the Aryson Office 365 Backup & Restore Tool. It allows you to back up all your archive emails to your local system in formats like PST, MBOX, EML, or PDF. Once your backup is safely stored, you can delete older emails from your mailbox to clear up space on the server. Along with that, it will keep your mailbox clean and run smoothly. So that your data stays safe and accessible.

Follow these Steps to Free Up Server Space and Increase Mailbox Size 

• Open the Aryson Office 365 Backup & Restore Tool and click Backup to proceed with.
• Then, enter your Microsoft 365 credentials (user ID and password) and sign in.
• Now, you can choose Archive Mailbox to back up your Exchange Online archive data.
• Pick any of the given formats and mark free up server space option along with saving path.
• To increase mailbox size in Microsoft 365 Exchange Online, click on the Convert Button.

Conclusion

If your mailbox hits the storage space on your system, it can slow down your work and stop emails from coming in. Hence, we provided some easy ways to increase your storage. You can turn on archive mailboxes, use PowerShell, or switch to a plan that gives you more space. Just make sure of your mailbox size and take action before it reaches the limit. That way, your emails will keep working smoothly without any problems. Other than that, you can take backup of your Office 365 data. Thereafter, you can free up server space to increase mailbox size in Microsoft 365 exchange online.

Frequently Asked Questions (FAQs)

About The Author:

Rohan Wiese

Rohan Wiese is a Technical Writer at Aryson Technologies. He is an expert Email Forensic, Cloud Computing, and a passionate nerd with over 10 years of experience in technical content writing. He writes about Cloud Migration, Database Recovery, Email Backup, Windows, Mac, and Tech.