Office 365 global administrators can now send the emails of size 150 MB. Microsoft has increased the maximum attachment size from 25 MB to 150 MB allowing users to send large file attachments in the mail when needed. Increasing the total attachment size directly from 25 MB to 150 MB is a good jump, and will certainly be useful for the users who often want to send the larger sized attachments.
Office 365 supports 150 MB email attachments
Specifically, increasing the total attachment size to 150 MB means that the users can send multiple attachments of various sizes, making it a total of 150 MB. The default size per attachment is for Office 365 mailboxes is still 25 MB. Office 365 also allows users to save and share their files via their OneDrive for Business account.
Note that you can send an email with the attachment of 150 MB size file, but the recipient can receive it only if the mailbox is hosted in the cloud and is configured to receive 150 MB size messages.
OWA … restricts the size of the message you can send to 25 percent less than the configured allowed maximum send size … For example, if your maximum allowed send size is set to 100 MB then using OWA you can only send up to 75 MB maximum. Additionally, in OWA, each attachment can be no larger than 25 MB. So with a 100 MB maximum send size, using OWA you could attach and send up to three 25 MB files in a single message.
Additionally, Microsoft also allows users to customize the maximum allowed attachment size for their mailboxes. You can restrict the attachment size to 5MB or allow the 100 MB size for everyone. In a nutshell, you can customize the configuration on your own preferences; adjust the mail attachment sizes for some or for all between 1MB to 150 MB. However, you require global administrator role privileges for that.
Check out the step by step guide by Microsoft for customizing the maximum message size.
This post lists the Attachment Size Limits for Outlook, Gmail, Yahoo, Hotmail, Facebook and WhatsApp.