Online Video Compressor
Use Online Video Compressor, review the result, and keep the original until the output is checked.
How to use Online Video Compressor
- Add the video files you want to shrink; up to 50 are accepted per batch.
- Start on Balanced quality and use the CRF slider - higher means smaller, and the range on this page begins at 28.
- Switch to Advanced bitrate only when you need a specific bit rate, then set Video Bitrate and Audio Bitrate yourself.
- Pick a size under Choose an output size to drop pixel count as well as bitrate, since resolution is where the biggest savings are.
- Press Compress Video and read the percentage on each row: a 6 second 611 KB test clip came back at 286 KB, about half the size, at the default CRF.
- Leave Format on MP4 when the goal is the smallest file - switching to WebM changes the encoder to VP9, and the same clip came back 34% larger after a noticeably longer wait.
What Online Video Compressor actually does to your file
How much you save depends on how tightly the source was already encoded - a recent phone or camera file usually halves, while a very short or very noisy clip can still leave slightly larger, because the encoder spends bits on artefacts it has to invent. Compression always decodes and re-encodes, so each pass costs detail permanently. The engine is a 25 MB wasm download and needs a secure (HTTPS or localhost) page, and long or large clips are bounded by your tab’s memory rather than a server.
Online Video Compressor FAQ
What does Online Video Compressor do?
Easily reduce video file size online with our free video compressor. Compress MP4, MOV, AVI, MKV, and more while keeping high quality—fast, secure, and no downloads required!
Which files work with Online Video Compressor?
This category commonly supports MP4, MOV, AVI, MKV, WMV, FLV, WebM, and 3GP. Use the accepted file types shown in the uploader, because support varies by browser and by the engine behind each tool.
Does compressing reduce the quality?
Yes, size comes from discarding detail. Start near the middle of the quality range and look at the result; if it is not small enough, lower the quality rather than re-compressing the same file several times, because each pass loses more.
Will my original file be changed?
No. The work is done on a copy in this tab by a WebAssembly build of ffmpeg, and the result arrives as a separate download, so your original is still there if you need it.
How is my file processed?
It is not uploaded. The processing is done locally by a WebAssembly build of ffmpeg, so the practical ceiling is your device's memory and the limit shown beside the uploader - no queue, no account, no copy on a server.
Is the Online Video Compressor free?
Yes. The Online Video Compressor is free with no trial limit, subscription, or watermark on downloads. You can use it for personal and commercial projects without creating an account.