How do I compress a video for email?
Get it under about 18 MB. Gmail, Outlook.com and Yahoo Mail cap a message at 25 MB, and email turns attachments into text that is about a third bigger, so 18 MB stays under 25 MB either way. Our free online video compressor has an email setting that aims there, in your browser, without uploading the video.
We make OctoZip and the online video compressor, so read the tool steps with that in mind. The email limits come from Google's, Microsoft's and Yahoo's own help pages, checked on 1 November 2026. The sizes are worked out by the compressor's own code for a typical phone video; real results vary.
What are the email size limits?
25 MB for the whole message on the three big free services:
| Service | Limit | Over the limit |
|---|---|---|
| Gmail, personal account | 25 MB of attachments in total | Gmail removes the attachment and adds a Google Drive link |
| Outlook.com | 25 MB for the email, including text and files | Attach it as a OneDrive file instead |
| Yahoo Mail | 25 MB of attachments, sending and receiving | Not described |
| Work or school accounts | Set by the administrator | Ask whoever runs the account |
Checked on 1 November 2026. More services, and the limits for work Outlook, are in email attachment size limits.
Why 18 MB and not 25?
Because email carries attachments as text. The standard way to do that, Base64 in RFC 2045, turns every 3 bytes into 4 characters, so an attachment travels about a third bigger: 18 MB × 4 ÷ 3 = 24 MB. The providers' pages don't say whether they count the file before or after that, so 18 MB fits either way, with room for the message text. A 25 MB file may be accepted by one server and refused by the next.
How long a video fits in 18 MB?
About 1 minute looks good, up to about 3 minutes is watchable on a phone, and beyond that send a link. The sum is 18 × 8 × 0.95 ÷ seconds for picture and sound together, so a 3-minute video gets 18 × 8 × 0.95 ÷ 180 = 0.76 Mbps.
| Length of a 1080p phone video | Original size | With the email setting | How it looks |
|---|---|---|---|
| 1 minute | 129 MB | 720p, about 17 MB | Good on a phone or laptop |
| 1½ minutes | 193 MB | 540p, about 17 MB | Fine on a phone |
| 2 minutes | 258 MB | 480p, about 17 MB | Soft on a big screen |
| 3 minutes | 387 MB | 360p, about 17 MB, sound re-encoded | Watchable on a phone |
| 10 minutes | 1.29 GB | 240p | Too small to be useful: send a link |
Estimates from the compressor's planning code for a video recorded at 1080p, 30 fps and 17 Mbps with stereo sound. It picks the resolution the budget can carry, following Android's guide to sharing video, which pairs 1.5 Mbps or less with a picture smaller than 720p.
How do I compress a video for email in my browser?
Open the compressor with the email setting, choose the video and compress. It works in recent Chrome or Edge on phones and computers, and the video never leaves your device.
Compress for email in your browser
- Open the compressor set for email. It shows "Set for email: under 18 MB".
- Tap Choose a video. If the video is too long to fit, the page says so and gives the smallest size that still looks like video.
- Tap Compress video and keep the tab open until it finishes.
- Play the copy, then Download it and attach it to your email, or on a phone tap Share and pick your mail app.
If your work account allows more, change the size: type 25 for a 35 MB limit (25 × 4 ÷ 3 = 33 MB), for example.
How do I compress a video for email on Android with an app?
With OctoZip, choose Small file, check the new size and share it to Gmail or Outlook. The app works without an internet connection and never uploads the video, but it has no size-in-MB option, so you read the result.
- Install OctoZip from Google Play, open it and tap Pick a video.
- Under Quick Compression, choose Small file (easy share), about a third of the resolution. For a clip under a minute, Medium file keeps more detail. Tap Apply.
- Tap Start Compression, then read the size on the result screen. Over 18 MB? Trim the video in your gallery's editor first, or send a link.
- Tap Share and choose Gmail or Outlook.
The app is free with no ads; free users see a full-screen Pro offer after every second saved video. It runs on Android 7.0 or later. More detail, including Gmail's Drive link on a phone, is in sending a large video by email from Android.
How do I compress a video for email on a Mac or Windows PC?
The online compressor works the same way in Chrome or Edge on a computer. With what's already there:
- Mac: open the video in QuickTime Player and choose File › Export As › 480p (Apple's guide lists 4K, 1080p, 720p and 480p). That sets the resolution, not the size, so check the file size in Finder before you attach it.
- Windows: in the Clipchamp video editor, export at 480p or 720p; Microsoft's help lists 480p, 720p, 1080p and 4K, with 1080p the largest free one. It too picks a resolution, not a size. See our Clipchamp comparison.
- Any computer with HandBrake: its Social 25 MB presets keep a video up to a set length under 25 MB, but they don't allow for email's text overhead, so check the size. See our HandBrake comparison.
What if the video is too long for email?
Send a link instead, or trim it. Gmail already does this for you: over 25 MB, it removes the attachment and adds a Google Drive link. Outlook.com suggests attaching the file from OneDrive. A link keeps the full quality, which matters for anything longer than a few minutes. For the other routes, see how to send a large video.
Questions people ask
Why does my email bounce when the video is under 25 MB?
Usually because the encoded attachment is about a third bigger, or because the other person's server has a lower limit. Compressing to 18 MB avoids the first; a link avoids both.
Can I zip a video to email it?
It barely helps. Video is already compressed, so a ZIP of an MP4 is about the same size. Lower the resolution instead, as above.
Does Gmail compress videos?
No. Over its limit, Gmail swaps the attachment for a Google Drive link rather than shrinking it. See compressing a video without an app for what Google's own apps do.
Can I email a video from an iPhone this way?
The online compressor also opens in Safari, though it's slower there and sometimes stops part way on long videos. These steps are written for Android phones and computers; the iPhone's own ways, including Mail Drop, are in how to compress a video on iPhone.
What this page doesn't cover
- Work and school accounts set their own limits, and some servers refuse attachments for other reasons, such as file type rules.
- The sizes are the compressor's estimates for one kind of video. A video saved from a chat app is already compressed and shrinks less.
- The online compressor does one video at a time, up to about 1–2 GB, and is made for recent Chrome and Edge. The OctoZip app has no size-in-MB option and no trim.
Sources
Checked on 1 November 2026.
- Gmail Help: attachment size limits.
- Microsoft Support: Unable to attach files in Outlook.com and choosing an export resolution in Clipchamp.
- Yahoo Help: message size limits in Yahoo Mail.
- IETF: RFC 2045, section 6.8 (Base64).
- Apple Support: Export movies in QuickTime Player on Mac.
- Android Developers: Best practices for sharing video.
- OctoZip: the online compressor's planning code, which gave the sizes above, and the app's code.