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ConvenTools

Compress Video — Shrink File Size in Your Browser

Runs in your browser — your files never leave your device

Shrink a video’s file size right in your browser. Choose a quality level, and the tool re-encodes it to a smaller MP4 — showing how much you saved. Your video is never uploaded.

Drop a video here, or click to choose
Compressed on your device — nothing is uploaded.

How to use it

  1. 1
    Choose a video

    Drop a video onto the drop zone, or click to select one.

  2. 2
    Pick a quality

    Choose Best quality, Balanced or Smallest depending on how much to shrink.

  3. 3
    Compress

    Click Compress. The first run loads the encoder (~30 MB) once.

  4. 4
    Download

    Check the size saved, preview the result, and download the smaller MP4. Nothing was uploaded.

Quality vs size

Compression trades a little visual quality for a much smaller file. “Best quality” keeps it close to the original; “Smallest” squeezes hardest. The result is a widely-compatible H.264 MP4, and you can see the before/after size before downloading.

Private, in-browser encoding

A WebAssembly build of ffmpeg does the work inside the page, so the file never leaves your device. Because it re-encodes the video, it is best suited to short clips; the first run loads the encoder (~30 MB) once.

Frequently asked questions

Is my video uploaded to a server?

No. Compression happens entirely in your browser with a WebAssembly build of ffmpeg — your video never leaves your device.

How much smaller will it get?

It depends on the source and the quality level you pick. The tool shows the before/after size and the percentage saved after compressing.

What format is the output?

A widely-compatible H.264 MP4, which plays on virtually any device or platform.

Is there a size limit?

Because it runs in your browser, very large or long videos can be slow and memory-heavy. Short clips compress best.