How it works
- Drop your video. MP4, MOV, WebM or MKV, any length. MOV files from an iPhone and MKV files from OBS work too.
- 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.
What you get
An MP4 with H.264 video and AAC audio, the most widely playable combination there is, with the index at the front of the file so it starts playing straight away when streamed. Rotation from phone videos is applied, so the result plays the right way up everywhere.
Formats in
MP4, MOV, M4V, WebM and MKV with H.264, HEVC, VP8, VP9 or AV1 video. Whether a codec can be decoded depends on your browser and device: HEVC (most iPhone videos) needs Safari, or Chrome or Edge on a computer with HEVC hardware support. The tool tells you straight away if your browser can't read the file.
| Length | 10 MB | 20 MB | 50 MB |
|---|---|---|---|
| 30 seconds | 1080p | 1080p | 2160p |
| 1 minute | 720p | 1080p | 1440p |
| 3 minutes | 360p | 540p | 720p |
| 10 minutes | 240p | 240p | 480p |
What the automatic setting picks for a 4K, 30 fps video with sound (smaller sources stay at their own size). Fast-moving footage looks softer at the same size; you can always override it.
Questions
Is this an online MP4 compressor?
It works like one: open the page and drop a file. But the compression runs in your browser, not on our server, so nothing is uploaded and there is no size cap or queue.
Can it compress MOV to MP4?
Yes. Any MOV your browser can decode becomes a smaller MP4.
Does it add a watermark?
No. No watermark, no sign-up and no limit on how many files you compress.
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.