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AVIMKV

Convert AVI to MKV

This free AVI to MKV converter changes your Audio Video Interleave (.avi) file into a Matroska Video (.mkv) file, right in your browser. There is nothing to install, no account to create, and no limit on how many files you convert.

100% private. Your file is processed locally in your browser with WebAssembly — it is never uploaded to a server, stored, or seen by anyone.

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The conversion runs on your own device using ffmpeg compiled to WebAssembly (ffmpeg.wasm), so your file is never uploaded to a server. MKV is best for archiving with multiple tracks and subtitles, which is the usual reason to convert from AVI.

Why convert AVI to MKV?

  • AVI and MKV are similarly compatible, so you are mainly changing the container.
  • The video is re-encoded to efficient H.264, so the MKV file is usually about the same size as your AVI.
  • Pick MKV when you need a file made for archiving with multiple tracks and subtitles.

AVI vs MKV

PropertyAVIMKV
Full nameAudio Video InterleaveMatroska Video
ContainerAVIMatroska
Typical codecMPEG-4 / MJPEGH.264 / H.265
CompatibilityLimitedLimited
Relative sizeLargestMedium
Best forOlder Windows software and archivesArchiving with multiple tracks and subtitles

How to convert AVI to MKV

  1. Add your AVI file

    Drag and drop your .avi file onto the upload area, or click to browse and pick it from your device.

  2. Start the conversion

    Click "Convert to MKV". Everything runs locally with ffmpeg compiled to WebAssembly (ffmpeg.wasm) - your file stays on your device.

  3. Wait a few seconds

    A progress bar shows the conversion. The first run is slightly slower while the engine loads, then it is cached.

  4. Download your MKV file

    When it finishes, download the .mkv file straight to your device.

Frequently asked questions

Is this AVI to MKV converter free?
Yes. It is completely free with no signup, no watermark, and no limit on how many files you convert. It is supported by ads, which keeps the conversion itself free.
Are my files uploaded to a server?
No. The conversion runs locally in your browser using ffmpeg compiled to WebAssembly (ffmpeg.wasm), so your file is processed in memory on your own device and is never uploaded, stored, or seen by anyone.
Will I lose quality converting AVI to MKV?
The video is re-encoded to MKV with a high-quality setting, so the result looks very close to the original AVI. Re-encoding is never bit-for-bit identical, but the loss is minimal.
Will the file get smaller or larger?
Usually similar. The video is re-encoded to H.264 at a high-quality setting, so the MKV file is typically about the same size as your AVI; the container itself adds little.
What is the difference between AVI and MKV?
AVI is Audio Video Interleave (an AVI container, typically MPEG-4 / MJPEG); MKV is Matroska Video (a Matroska container, typically H.264 / H.265). MKV is best for archiving with multiple tracks and subtitles, while AVI is best for older Windows software and archives.
How long does the conversion take?
Most files finish in a few seconds to under a minute, depending on length and your device. The first conversion is a little slower while the engine downloads and caches, then later runs start instantly.

Related conversions

MP4 → MKVMOV → MKVAVI → MP4AVI → WebMAVI → MOVAVI → MP3

Need more formats or options? Use the full Change Video Format.