MultiKit

Video Compressor: Make a Video File Smaller, No Upload

  • Free
  • No sign-up
  • Runs in your browser
  • Version 1.0.2
  • Last updated 2026-10-25
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Shrink a video so that it fits an e-mail, a chat app or an upload limit. Choose a lower size and a quality, or give a size in MB to aim for. Your device does the work and nothing is uploaded.

What this browser can make

    This depends on your browser, not on MultiKit. Chrome and Edge support the most.

    Everything you enter is processed in your browser and is never sent to a server.

    Browsers:Chrome94+Edge94+Firefox130+Safari16.4+Opera80+Samsung Internet17.0+BrowsersWhich formats it can read and write also depends on your browser and device; the tool shows what yours can do.

    How to use

    1. Drop the video onto the box, or choose it. Its size, length and format are shown.
    2. Choose a size (720p is a good start) and a quality. Smallest file makes the smallest result; Best picture keeps more detail.
    3. Or give a size in MB under Aim for a file size. The picture quality is then chosen to fit. Tick Remove the sound to save a little more.
    4. Press Convert, then compare the sizes shown and press Download. If the result is not smaller, the page says so.

    Examples

    A 100-second 1080p video, to 720p, Balanced
    → About 26 MB
    1280 × 720 × 30 frames × 0.07 bits ≈ 1.9 Mbps, plus 128 kbps sound.
    The same video, aim for 10 MB
    → About 656 kbps of picture
    10 MB × 0.98 × 8 ÷ 100 s, less 128 kbps of sound.
    A 10-minute video, aim for 1 MB
    → The page refuses
    The size is too small for the length; it asks for a larger size or a shorter part.

    How it works

    This page is the video converter set up for making files small. The picture is written again at a bitrate worked out from its size and frame rate (0.04, 0.07 or 0.11 bits per pixel per frame for Smallest, Balanced and Best), or from the size you aim for: the bitrate is the target size, less 2 percent for the file’s wrapping, spread over the length, less the sound’s 128 kbps. If that leaves less than 100 kbps for the picture, the page refuses instead of making an unwatchable video.

    The work is done by the WebCodecs of your browser through the open-source Mediabunny toolkit (MPL-2.0). The size you ask for is an aim: the actual file can differ by some percent. This page uses the audio and video codecs built into your browser, so what it can read and write depends on the browser. The list under the tool shows what yours can make. Chrome and Edge support the most.

    Choose size, quality and compatibility

    • Quick sharing: Balanced is the safest first try; reduce the dimensions as well when a phone recording is larger than the screen where it will be watched.
    • Target-size uploads: enter a size just below the service limit because container overhead and codec behavior make the result an estimate, not an exact cap.
    • Input and output: supported formats and codecs depend on this browser; the capability list below the tool is the authoritative list for this device.
    • Privacy and limits: frames are decoded and encoded locally. Long or high-resolution videos need substantial time, memory and battery, and an older browser may support fewer outputs than Chrome or Edge.

    Sources

    Frequently asked questions

    How much smaller will it be?
    It depends on the original. Phone and camera videos are often written with very high bitrates and shrink a lot; a video that is already small may not shrink, and the page says if the result is larger.
    What costs the most quality?
    Aiming for a size that is too small for the length: the picture becomes blocky. A lower size such as 720p keeps a small file sharp better than squeezing 1080p.
    Which size should I choose for chat apps?
    Many apps limit a file to 8 to 25 MB. Choose 480p or 720p and aim for a size just under the limit.
    Can I also cut the video?
    Yes. Type a start and an end to keep only a part, which is the best way to make a long video small.
    Why can I not choose some format?
    This page uses the audio and video codecs built into your browser, so what it can read and write depends on the browser. The list under the tool shows what yours can make. Chrome and Edge support the most.
    Is my video uploaded?
    No. It is compressed in your browser.
    Version history
    • 1.0.2 — Adds a practical decision guide covering best-fit uses, inputs and outputs, privacy, quality trade-offs and known limits.
    • 1.0.1 — Makes the search title and description state the supported task, key formats and privacy benefit more clearly.
    • 1.0.0 — First release.

    Last updated: