Top 2 Methods to Increase Attachment Size in Office 365

May 19, 2021 | Posted by: Deepak Singh Bisht

increase email size limit office 365

Recently, Microsoft Office 365 increased the attachment size limit from 25 MB to 150MB. For the last couple of years, the message size was 25 MB which includes, both text and attachment. After this update, the Office 365 administrators can set the maximum message size limit from 1 MB to 150 MB.

In this post, we will discuss how to increase the mail Attachments Size limit in Office 365 and how to successfully implement the manual methods to increase email attachment size limit in Office 365.

Method 1: Increase email size limit using the Exchange Admin Center

In this method, we will use the Exchange Online admin center to increase the mail size limit.

Sign in your Office 365 Account

Click on Admin centers and select Exchange

exchange admin center screen

From the Exchange admin center, select recipients and click on Mailboxes.

admin mailboxes option

Click on … icon and select Set default message size restrictions.

default message size restrictions option

From the default message size restrictions popup, set Maximum size for sent message and received message and Click on OK.

email size setup screen

Increase email size limit for multiple user using the Bulk Edit

Select All Mailboxes, under the Bulk Edit, select message Size Restrictions and click on update.

bulk export option

From the Bulk edit message size restrictions screen, set Maximum size for sent message and maximum size for received message and Click on the Save.

bulk email size setup screen

Method 2: Increase Office 365 attachment size limit using PowerShell Command

This is the most preferred method. Mainly it used by small and large organizations.

Phase 1: Login Office 365 account by using PowerShell


Type above command and hit the Enter key. Now, type Office 365 username and password.

Phase 2: Once you login, type the following command.

$Session=New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri -Credential $Cred -Authentication Basic -AllowRedirection

Phase 3: Now, type the following command to import the PSSession

Import-PSSession $Session

Phase 4: You can select the below command as per your requirement.

  1. Update single mailbox

    Set-Mailbox -Identity [email protected] -MaxSendSize 100MB -MaxReceiveSize 100MB

  2. Update multiple mailboxes

    (“user1”,” user 2”,” user”)|%{Set-Mailbox -Identity $_-MaxSendSize 100MB-MaxReceiveSize 100MB}

  3. Update all mailboxes

    Get-Mailbox | Set-Mailbox -MaxSendSize 100 MB -MaxReceiveSize 100 MB

  4. Update the default mailbox settings (helpful for the mailbox in the future)

    Get-MailboxPlan | Set-MailboxPlan -MaxSendSize 100MB -MaxReceiveSize 100MB

Frequently Asked Questions

How to check email attachment size limit in Exchange and Office 365?

To check attachment size limit, use the following PowerShell command.

  1. Get-TransportConfig | Format-List MaxReceiveSize,MaxSendSize,MaxRecipientEnvelopeLimit
  2. Get-ReceiveConnector | Format-Table Name,Max*Size,MaxRecipientsPerMessage
  3. Get-SendConnector | Format-Table Name,MaxMessageSize

For Office 365, use Get-InboundConnector & Get-OutboundConnector instead of Get-ReceiveConnector & Get-SendConnector.

What is the largest message size you can email?

Recently, Microsoft increased the message size limit to 150 MB which means you can send a message from 1 MB to 150 MB.

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