Guide
What is the Outlook attachment limit?
25 MB on Outlook.com, 20 MB by default in the desktop app, often less at work. Beyond that, a link: up to 5 GB here, without an account.
The Outlook limit, plainly
| Outlook.com | 25 MB per attachment |
|---|---|
| Outlook on a computer (IMAP, POP account) | 20 MB by default |
| Work account (Exchange) | Set by the administrator: 10 MB by default on an Exchange server, 35 MB to send on Microsoft 365 |
Sources: Outlook help, Microsoft Learn — October 2026.
How to send bigger
A TransferThing link
Drop the file here, paste the link into your message. Up to 5 GB, without an account for you or the recipient.
A OneDrive link
Outlook offers to share the file from OneDrive, up to 2 GB. It uses your OneDrive storage.
Zip or split
A .zip barely shrinks videos, photos or PDFs. Several messages work, but your recipient has to put everything back together.
A free account to follow your transfers.
See what was downloaded, and find your links again.
Frequently asked questions
What is the maximum attachment size in Outlook?
25 MB on Outlook.com. In Outlook on a computer, 20 MB by default for a personal e-mail account (IMAP or POP). On a work account, the administrator sets the limit.
Why does my work e-mail refuse smaller files?
An Exchange server caps messages at 10 MB by default, Microsoft 365 at 35 MB to send; your administrator can change these values.
Can I raise the 20 MB limit?
In Outlook on a computer, yes, with a Windows registry setting Microsoft describes; your recipient’s server may still refuse the message.
How do I send a large file with Outlook?
Drop it on TransferThing, copy the link and paste it into your message: up to 5 GB, without an account. Or share it from OneDrive, up to 2 GB.
Does the recipient need a Microsoft account?
For a OneDrive link, it depends on the sharing you choose. For a TransferThing link, no: they download in their browser.
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