How to Set Office 365 Mailbox Quota

Office 365 Mailbox Quota Limits

You can control the size of Office 365 mailboxes with mailbox quotas. Mailbox quotas has three settings:

  • Warning limit – when the mailbox reaches this limit a warning is sent to the user
  • Send limit – when the mailbox reaches this limit the user can’t send emails anymore
  • Send/receive limit – when the mailbox reaches this limit the user can’t send or receive emails

By default the warning limit is set to 98% of the mailbox capacity, the send limit is set to 99% of the mailbox capacity and the send/receive limit is set to 100% of the mailbox capacity.

As mailbox sizes varies depending on the type of Office 365 license the actual limits are as follows:

Office 365 Mailbox Quota Limits

Limit TypeExchange Online KioskExchange Online Plan 1Exchange Online Plan 2
Warning1.96 GB49 GB98 GB
Prohibit Send1.98 GB49.5 GB99 GB
Prohibit Send/Receive2 GB50 GB100 GB

The following table shows what Licensing Plans are using what Service Plans:

Licensing Plan / Service Plan Reference Table

Licensing PlanService Plan
Office 365 Enterprise F1Exchange Online Kiosk
Office 365 Business EssentialsExchange Online Plan 1
Office 365 Business PremiumExchange Online Plan 1
Office 365 Enterprise E1Exchange Online Plan 1
Office 365 Enterprise E3Exchange Online Plan 2
Office 365 Enterprise E5Exchange Online Plan 2

Setting Office 365 Mailbox Quota Using AD Users & Computers

To enable the configuration of Office 365 mailbox quotas via the Active Directory Users & Computers tool, you must install the Easy365Manager snapin.

Once the snapin is installed, you’ll see two new tabs on user properties: The Office 365 tab and the Mailbox tab. Use the latter to view and configure the mailbox quotas on the Exchange Online mailbox:

Easy365Manager user properties, Office 365 mailbox management inside Active Directory

As you can see, other Exchange Online mailbox properties are also configurable via the new tab.

The many settings available allow you to perform all daily management tasks in AD Users & Computers and removes the need to constantly switch back and forth between the various Office 365 management tools.

Read the full feature list of Easy365Manager here.

You can download a fully functional free 30-day trial here.

Setting Office 365 Mailbox Quota Using PowerShell

Office 365 mailbox quotas are not configurable via the Exchange Admin Console. Without Easy365Manager, you need to use PowerShell.

Use the Set-Mailbox command to configure mailbox quotas after connecting to Exchange Online:

# Connect to Exchange Online
Connect-ExchangeOnline
# Set the mailbox quota
Set-Mailbox tycho.brahe@observatory.dk -IssueWarningQuota 230MB -ProhibitSendQuota 240MB -ProhibitSendReceiveQuota 250MB
# Disconnect to avoid session depletion
Disconnect-ExchangeOnline

Remember to disconnect your Exchange Online session when finished to avoid session depletion.