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Video compressor. Your footage never leaves.

Read the written guide A free online tool by Digital Heroes

Heads up: your first compression downloads a one-time video engine (about 25 MB) from a public CDN. After that it runs entirely on your device. The video itself is never uploaded.

Drop a video here

or click to browse, MP4, WebM, MOV, MKV, AVI & more

Your video never leaves your browser.

Why compress video in the browser?

Most “free” video compressors upload your footage to a server, slow, and your private clips end up on someone else’s machine. This tool runs a WebAssembly build of FFmpeg directly in your browser, so the whole job happens locally and the file never leaves your device. The trade-off is speed: a server farm is faster than your laptop, so long videos take a while. For big batches or very large files (300 MB+, especially on Safari), a desktop app is still the better tool, this one is for quick, private, no-install jobs.

§ · written guide

How to use the Video Compressor

This compressor shrinks a video file inside your browser and saves it as an MP4. It runs a WebAssembly build of FFmpeg that re-encodes the picture with H.264 at the strength you pick, can lower the resolution and frame rate, and can drop the audio. It is meant for quick, private jobs, such as making a clip small enough to email or upload.

Step by step

  1. Add a video

    Drop a file on the card that says Drop a video here, or click it to browse. MP4, WebM, MOV, MKV, AVI and similar files work. The Source panel shows a preview with the file size, length and dimensions.

  2. Pick a compression strength

    Choose High quality, Balanced or Strong. They use CRF 23, 28 and 33; a higher CRF gives a smaller file with more visible loss. Balanced is selected by default.

  3. Cap the resolution and frame rate

    In Resolution cap, choose 1080p, 720p or 480p to limit the long edge to 1920, 1280 or 854 pixels, or keep the original. In Frame rate, choose Cap at 30 fps or Cap at 24 fps, or keep the original. Smaller videos are never upscaled.

  4. Decide on audio

    Tick Mute (remove audio track) to drop the sound. Otherwise the audio is re-encoded as AAC at 128 kbps.

  5. Compress

    Press Compress video. The first run downloads the engine, about 25 MB, and then the bar and the status line show the percent done. Press Cancel to stop a run.

  6. Download the result

    When the Result panel appears, play it to check, then press Download MP4. The file keeps your original name with -compressed added. Press Choose another file to start again.

Reading the result

  • The large number in the Result panel is the change in size: a minus value is the share saved, and a plus value means the output grew. The line under it shows the original size and the new size.
  • If the output is larger than the input, the source was already well compressed. Try Strong or a lower resolution cap.
  • The output is always an MP4 with H.264 video, even pixel dimensions and fast start, so it can begin playing before it has fully downloaded.
  • If Compression failed appears, the file probably uses a codec the engine cannot read. Convert it to MP4 with another tool first. A message that the engine could not load means the download from the CDN was blocked; check your connection or try another browser.

Tips and common mistakes

  • The frame rate option sets the output to exactly that rate, so only choose a value lower than your source. Picking 30 for a 24 fps clip adds duplicate frames.
  • Lowering the resolution gives the biggest saving on phone footage, and capping a 60 fps screen recording at 30 fps also helps a lot.
  • Compression runs on your device, so it is slower than a server. The page's own estimate is 0.3 to 1 times video speed, which means a 2 minute clip can take 2 to 6 minutes.
  • Changing the compression strength clears the previous result, so download it first if you want to compare two settings.
  • Files over 300 MB show a warning. They may work, but the engine has a memory ceiling of about 2 GB and Safari is stricter, so try a shorter clip if the tab crashes.

Privacy and limits

Your video is read and encoded by your own browser and is never uploaded. The first run downloads the FFmpeg engine, about 25 MB, from cdn.jsdelivr.net, and later runs on the same page reuse it. Nothing is saved. The tool needs WebAssembly and shows a notice when the browser cannot run it.

Back to the tool

§ 02 · what you can do

Everything a compressor should do.

Compress MP4, WebM, MOV & moreDrop almost any common video container and shrink it, nothing is ever uploaded.
Three quality presetsPick High quality, Balanced or Strong (CRF 23 / 28 / 33) to trade size against fidelity.
Cap the resolutionDownscale to 1080p, 720p or 480p to cut file size dramatically on phone footage.
Limit the frame rateCap at 30 or 24 fps, perfect for shrinking 60 fps screen recordings.
Mute the audioRemove the audio track entirely with one checkbox, or keep it as AAC 128 kbps.
Web-ready MP4 outDownload an H.264 MP4 with fast-start enabled, so it streams instantly on the web.
§ 04 · faq

Frequently asked questions.

Is the Video Compressor free?
Yes, completely free for everyone. No sign-up, no account, no watermark and no usage limits.
Is it private? Is my video uploaded anywhere?
No upload, ever. The compressor runs entirely in your browser on your own device, your video never leaves your computer and nothing is sent to a server.
Why does the first run take a moment?
The first time you compress a video, your browser downloads a one-time engine of about 25 MB (a WebAssembly build of FFmpeg). It is cached afterwards, so later runs skip the download and can work offline.
Why is compression slower than an online converter?
Because the encoding happens on your device instead of on a server farm. That is the trade-off for privacy, expect roughly 0.3-1× video speed, so a 2-minute clip may take 2-6 minutes depending on your hardware.
What formats can I use, and what do I get back?
You can drop MP4, WebM, MOV, MKV, AVI and most other common containers. The result is always a web-ready MP4 (H.264) with fast-start enabled. Some exotic codecs may not decode, if so, convert to MP4 first.
What is the largest file I can compress?
The engine runs in WebAssembly with a roughly 2 GB memory ceiling, and Safari is stricter. Files over 300 MB may work but can crash the tab, for very large videos, use a shorter clip or a desktop app instead.

Published · Last updated .

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