Compress a video to attach in Outlook
Outlook.com typically limits attachments to around 20 MB, and many company Exchange servers set their own caps — often 10–25 MB. Bigger files get turned into OneDrive links or bounce. Targeting 20 MB (or lower for work mail) keeps the video as a real attachment that opens in Windows' built-in player.
Last updated September 2026
Compress for Outlook (20 MB) →How to do it
- Open the compressor with a 20 MB custom target (the button below sets it).
- Load your video; trim to the part you need.
- Choose 720p for anything over a minute or two.
- Compress and download the MP4.
- Attach it in Outlook. If a work server rejects it, recompress to 10 MB.
Tips
- Corporate mail limits vary — if you don't know the recipient's server, 10 MB is the safe choice.
- Encoding overhead means a 20 MB file can exceed a 20 MB limit; the tool's safety margin helps, but 18 MB is safer still.
- MP4 (H.264/AAC) plays in Windows Media Player, Films & TV, QuickTime and phones without codecs.
FAQ
What is Outlook's attachment limit?
At the time of writing, Outlook.com typically allows about 20 MB per message. Desktop Outlook with Exchange uses whatever limit your organisation sets.
Why did my attachment bounce even under the limit?
The recipient's server may have a lower limit than yours. Try 10 MB, or share via a link.
Does this work for Outlook on Mac?
Yes — the tool runs in any modern browser, and the MP4 attaches the same way.