Quick answer: compress the video to about 18 MB for Gmail or 14 MB for Outlook, then attach it. Those targets are lower than the published limits on purpose — read why below.
The limits, and the hidden catch
| Email service | Published limit | Safe target for a video |
|---|---|---|
| Gmail | 25 MB (all attachments combined) | ~18 MB |
| Outlook.com | 20 MB | ~14 MB |
| Apple Mail with Mail Drop | 5 GB (sent as a link) | No compression needed |
The catch is encoding. Email can only carry text, so attachments are converted into text before sending, which makes them roughly a third larger. That’s why a 19 MB video can be rejected by a 25 MB limit. Leaving that headroom saves you the bounce-back.
Option 1: Let Apple Mail use Mail Drop
If you send from the built-in Mail app, you don’t need to compress at all. Attach the video and tap Send; when it’s too big, Mail offers Use Mail Drop. The recipient gets a link to download the full-quality file for 30 days. This doesn’t work from the Gmail or Outlook apps.
Option 2: Compress it to a target size
- Note which service you’re sending from (Gmail, Outlook, a work account).
- Compress the video to the safe target in the table above.
- Attach the smaller file from Photos or Files.
If you’d rather do it by hand, the video size calculator tells you the bitrate and resolution that fit your clip’s length. As a rule of thumb at 30 fps:
- Under 1 minute: 1080p usually fits 18 MB.
- 1–3 minutes: drop to 720p.
- 3–6 minutes: 480p, or trim it.
- Longer than that: share a link — no compression will look good at email sizes.
Option 3: Trim before you compress
Every second you cut is space the rest of the video gets to keep. In Photos, tap Edit, drag the ends of the timeline in, and tap Done › Save Video as New Clip so you keep the original.
Sending to a work account?
Company Microsoft 365 and Exchange accounts set their own caps — some as high as 150 MB, some as low as 10 MB. If a work email bounces, ask IT for the limit or compress to 10 MB to be safe.