How it works
- Drop your video. MP4, MOV, WebM or MKV, any length. The Gmail preset is selected; switch to Outlook if that's what you use.
- Pick where it's going. The tool works out the bitrate from the length and the limit, keeps room for the sound, and picks a resolution and frame rate that will still look clean. The estimated size and a real before-and-after frame update as you change things.
- Trim if you like, or set the resolution and frame rate yourself.
- Compress. When the encode finishes, the tool weighs the file. If it came out over the limit, it encodes again at a lower bitrate, so the file you download is always under the target, to the byte.
Why a 24 MB file won't attach to a 25 MB email
Email sends attachments as base64 text, which makes them about a third bigger. Gmail's 25 MB limit applies to that encoded message, so the largest file that really fits is about 18.7 MB, less the text of your email. Outlook.com's 20 MB works the same way. That's why the presets aim for the real file sizes:
| Service | Stated limit | We aim under |
|---|---|---|
| Gmail, Yahoo Mail | 25 MB | 18 MB |
| Outlook.com | 20 MB | 14 MB |
Work or school email often has a different limit set by your IT team; pick Custom and enter about three quarters of it.
Questions
What is the largest video I can email with Gmail?
Gmail allows 25 MB per message, counted after encoding, so the video itself should be under about 18 MB. Larger files are sent as a Google Drive link instead.
How do I send a long video by email?
Compress it here to 18 MB for Gmail or 14 MB for Outlook. If it's long, trim it or lower the resolution. Very long videos are better shared as a link.
Is my video uploaded?
No. Your browser reads the file from your disk and encodes it on your own device with WebCodecs. Nothing is sent to a server, so it also works on large private files.
Why does it say the file is guaranteed to be under the limit?
After encoding, the tool measures the real file. Video encoders can overshoot a bitrate by a few percent, so if the file is over the target the tool encodes again at a lower bitrate. It only offers the download once the byte count is under the target, and it shows both numbers.
Which browsers work?
Any browser with WebCodecs video encoding: recent Chrome, Edge, Firefox and Safari on a computer, and Chrome on Android. If yours can't, the tool says so instead of failing halfway. If your browser can encode VP9 but not H.264 with AAC, you get a WebM file and a note saying so.