Email attachment limits
Gmail, Outlook, iCloud Mail: 25 MB
Yahoo Mail: 25 MB
Most corporate email: 10–20 MB
1 minute of 4K iPhone video: ~400 MB (16× the limit)
How to Compress a Video to Send via Email
A 30-second clip from your iPhone is 200 MB. Email caps at 25 MB. There are three real ways to solve this — pick the one that fits your situation.
Option 1 — Share a Link Instead (Easiest)
No compression needed. Upload once, share a link.
Best when: the recipient just needs to watch it, not download the original.
Option 2 — Compress the Video File
When the recipient needs the actual file attached.
On Mac — using iMovie (free, built-in)
- 1Import your video into iMovie
- 2Add it to the timeline
- 3File → Share → File
- 4Set Resolution to 720p, Quality to "Medium"
- 5Export and check file size in Finder
A 400 MB 4K clip typically compresses to 15–30 MB at 720p Medium. Check before attaching.
On Mac — using MediaOptim (batch, more control)
- 1Drag video into MediaOptim
- 2Choose "Small" preset (targets under 25 MB for short clips)
- 3Compress — original is preserved
On iPhone — before sending
- 1Open the Photos app and find your video
- 2Tap Share → Mail
- 3iOS will prompt you to choose a size: Small, Medium, Large, or Actual Size
- 4Choose "Small" or "Medium" for email-safe sizes
Target File Sizes to Aim For
| Video length | Original (4K iPhone) | After compression (720p) | Email safe? |
|---|---|---|---|
| 30 seconds | ~200 MB | ~8–12 MB | ✓ Yes |
| 1 minute | ~400 MB | ~15–20 MB | ✓ Yes |
| 2 minutes | ~800 MB | ~30–40 MB | ✗ Too large |
| 5 minutes | ~2 GB | ~70–100 MB | ✗ Use a link |
For videos over 2 minutes, a shared link is always the better option regardless of compression.
Gmail tricks you into thinking it worked
If you attach a file over 25 MB in Gmail, it automatically uploads to Google Drive and inserts a link — without telling you clearly. The recipient gets a link, not an attachment. If you specifically need a file attachment, compress the video first and verify the size before attaching.