Introduction

This article describes the maximum attachment sizes for Exchange Online and Gmail email.

Explanation

Both VT Exchange Online and VT Gmail have their own limits for attached file sizes that change based on the address of both the sender and recipient. In this article, the address is either an Internal VT address (‘@vt.edu’) or an External address (not ‘@vt.edu’). Despite the limits listed below, it is recommended to keep all email attachments limited to 25 Megabytes (MB) or smaller per email. The best practice, however, is to share the document via link from a shared drive such as Google’s shared drives, Microsoft’s SharePoint, Microsoft’s OneDrive, or something similar as attachments go against your quota. These limits cannot be adjusted.

Regardless of your limit, delivery is not guaranteed. The recipient's mail server may have lower limits. the best practice is to send a link rather than the actual file. 

Exchange Online attachment size limits

Direction	Limits (Megabytes)
Internal VT to Internal VT	150 MB
External to Internal VT or A1 licenses	35 MB

 

Teams attachment size limits

When sending an email to a team or team channel, you are actually sending to the underlying M365 Group. The attachment limits for this group are described in the above section. However, Teams itself only allows 10 MB file sizes. So, it can look like it was sent successfully, but Teams never displays it.

Options are to check the email in the M365 Groups interface or to get the attachment size below 10 MB.

Direction	Limits (Megabytes)
Internal VT to Internal VT	10 MB
External to Internal VT or A1 licenses	10 MB

Gmail attachment size limits

Direction	Limits (Megabytes)
Internal VT to Internal VT	25 MB
External to Internal VT	50 MB