How to compress a video for email
The real attachment limits, why a 24MB file can still bounce, and the settings that reliably get a phone clip under them.
In short
Most providers cap attachments around 25MB, and encoding overhead means you should aim for 20MB. Smallest file plus a 720p cap clears it for most clips; if it does not, the clip is too long and needs trimming.
Attaching a video to an email fails more often than it works, because a couple of minutes off a phone is routinely ten times the limit.
The limits
| Provider | Limit | Behaviour past it |
|---|---|---|
| Gmail | 25 MB | Uploads to Drive and sends a link instead |
| Outlook / Microsoft 365 | 20–25 MB | Rejects, or offers OneDrive |
| Yahoo Mail | 25 MB | Rejects |
| Many corporate servers | 10 MB | Silently bounces, sometimes without telling the sender |
The settings that work
- 01
Trim to what matters
Duration is the most reliable lever. Ten seconds of a thirty-second clip is a third of the file gone before you compress anything.
- 02
Smallest file, capped at 720p
This is the largest reduction the tool offers. Detail softens in motion, and it stays perfectly clear in a message window — which is where an emailed clip is watched.
- 03
Check the reported size
The tool shows the before and after. If it is still over, trim harder or drop to 480p rather than running it twice.
When compression is not the answer
If a clip is several minutes long, no setting will make it a sensible attachment — 480p at the hardest preset will still be tens of megabytes and will look poor. Share a link instead, or split the clip and send the part that matters.
Mistakes worth avoiding
- Sending at exactly the limit. Encoding overhead pushes it over.
- Compressing the same file repeatedly until it fits. Go back to the original and pick a harder setting once.
- Emailing a clip that would be better as a link. A three-minute video is not an attachment.
Tools used in this guide
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