Compress a video to the size you need.
Say how big the file is allowed to be and the tool works out the bitrate and picture size to fit. If it comes out over, it tries again. The video stays on your computer.
Free for files up to 500 MB, with no watermark and no account.
Video compressor
This tool needs WebCodecs (the browser's built-in video encoder). Use a current Chrome or Edge on a computer, or a recent Safari. Nothing was uploaded and nothing will be.
Drop a video to compress
MP4, MOV, WebM or MKV. The file is read inside this page and goes nowhere else.
No upload. This page's security policy forbids network connections, so your video cannot leave it. See how to check that yourself.
How it works
Drop in the video
Nothing is uploaded. The browser opens the file from your disk and reads the length, size and codecs.
Choose the size
Pick a preset or type your own. The plan line tells you the picture size and bitrate it will use, or that the target cannot work.
Compress and check
Watch the progress, play the preview, and download. If the first try is too big it is re-encoded at a lower bitrate.
Why a target size and not a quality slider
Most video compressors ask for a quality setting and show you the size afterwards. That is the wrong way round when a service has a hard limit: an upload that is 200 KB over is refused just the same as one that is 200 MB over. Here you give the limit first, and the quality is whatever that limit allows.
What it does to your video
- Picks a bitrate from the target size, the length of the clip (after trimming) and whether you keep the sound.
- Scales the picture down when the bitrate is too low for the full size, because a smaller sharp picture looks better than a large blocky one. It never scales up.
- Caps the frame rate at 30 frames per second.
- Measures the result and, if it is over the target, encodes again at a lower bitrate.
- Tells you plainly when a target cannot be reached, instead of producing a poor file.
What it does not do
It does not edit: there is no cropping, filters or captions. It only trims the start and end and optionally removes the sound. The output is always an MP4, and a file that is already under your target is left as it is unless you choose to compress it anyway.
Questions
How does it make the file the exact size I asked for?
It works backwards from your target. The size of a video file is roughly its bitrate times its length, so the tool subtracts a bitrate for the sound, aims at 96% of your target for the picture and the container, and encodes. It then measures the real file. If the result is over the target, it re-encodes at a corrected bitrate, and it will not hand you a file that is bigger than the target.
Is my video uploaded anywhere?
No. The page cannot make network connections, because its Content-Security-Policy forbids them. The video is decoded and re-encoded by your browser using WebCodecs. The privacy page shows how to confirm that in your own browser tools.
What if my video is too long for the size?
The tool says so before it encodes anything. For example, a two-hour film cannot become 8 MB at any quality worth watching. It tells you roughly how much length does fit, and you can trim the video, pick a larger target or remove the sound.
What format is the result?
An MP4. Where your browser can encode it, the video is H.264 and the sound is AAC, which play almost everywhere. If your browser has no H.264 or AAC encoder, the tool falls back to VP9 or Opus and says so on the result.
Which browsers work?
It needs WebCodecs video encoding. Current Chrome and Edge on a computer have it. Safari and Firefox have added parts of it in different versions, so the page checks what your browser can do and shows a clear message instead of failing. A phone browser can work but is slower and may refuse large files.
Why not use ffmpeg in the browser?
ffmpeg compiled for the browser needs special server headers (cross-origin isolation) that this static site cannot send, and it is much slower than the browser's own encoder. WebCodecs uses the encoder already built into your browser and, often, your graphics hardware.
Is it free?
Yes for files up to 500 MB, one at a time, with any output size and no watermark. Pro is a one-time $19 for files of any size, a batch queue, hardware-encoder preference and remembered settings.