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AVI to MKV Converter

Convert AVI to MKV online for free. Fast, secure, and high-quality conversion with no sign-up or software required.

  • Free to use
  • No file stored beyond 1 hour
  • Encrypted over TLS 1.2/1.3
  • No watermarks

Drag and drop your files here or click to upload.

Maximum file size is 1GB

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How it works

Three steps to your converted file

Everything happens in your browser tab - upload, pick a format, download. The heavy lifting runs on our servers.

  1. 01

    Upload your file

    Drag and drop, click to browse, or paste a URL. Batches take up to 20 files at once - 230+ input formats across video, audio, image, document, and archive types.

  2. 02

    Choose an output format

    Pick from over a hundred output formats. Filter by category or search by name - every option is open to everyone, no account needed.

  3. 03

    Convert & download

    Hit Convert and grab your download link moments later. Originals are erased when the job completes; results are cleared within about an hour.

AVI to MKV

Why convert AVI to MKV?

AVI and MKV are both lossy formats.

  • Where MKV works best

    Movies with several audio tracks and subtitles.

AVI vs MKV: what's the difference?

PropertyAVIMKV
TypeVideoVideo
CompressionLossy (smaller files, some quality loss)Lossy (smaller files, some quality loss)
Opens inWindows players and VLC; not iPhone or most browsersVLC and most desktop players; few phones, TVs or browsers
Best forOlder Windows video filesMovies with several audio tracks and subtitles

What is an AVI file?

Audio Video Interleave

Developed By
Microsoft
Initial Release
1992
MIME Type
video/x-msvideo

Audio Video Interleave (AVI) is a multimedia container format introduced by Microsoft in 1992 as part of the Video for Windows technology. It adheres to the Resource Interchange File Format (RIFF) specification, storing audio and video data in tagged chunks (specifically 'movi' lists) to allow synchronous playback. While widely compatible, the legacy AVI architecture lacks native support for modern features found in MP4 or MKV, such as variable frame rates (VFR), B-frames, and sophisticated chapter markers. It typically utilizes codecs like DivX, Xvid, or MJPEG.

How to open an AVI file

AVI files enjoy broad compatibility on Windows via Windows Media Player. However, because AVI is a container that can hold various codecs (e.g., DivX, Xvid), playback may fail if the specific codec is missing. macOS users can view AVI files using QuickTime Player if the content is MJPEG, but third-party players are often required for other codecs. VLC media player and MPC-HC are standard recommendations for handling the vast array of codecs potentially encapsulated within an AVI file.

What is an MKV file?

Matroska Video Container

Developed By
Matroska (non-profit)
Initial Release
2002
MIME Type
video/x-matroska

The Matroska Video (MKV) file is an open-standard, free container format capable of holding an unlimited number of video, audio, picture, or subtitle tracks in one file. Unlike proprietary containers, Matroska is structured upon Extensible Binary Meta Language (EBML), allowing for significant flexibility and forward compatibility. It supports a vast array of codecs, including H.264, VP9, HEVC, AAC, Vorbis, and FLAC, and is particularly noted for its support of soft subtitles (SSA/ASS) and chapter entries, making it a standard for high-definition video distribution (HD) and anime fansubs.

How to open an MKV file

Native support for MKV is available in Windows 10/11 via the Movies & TV app and generally on Linux distributions. macOS requires third-party software, as QuickTime Player does not natively parse the Matroska container. The industry-standard solution for all operating systems is VLC Media Player, which includes built-in libraries for decoding the diverse codecs often encapsulated within MKV files. Alternative options include MPV and MPC-HC (Windows).

More tools

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Why RunConvert

The fastest way to convert any file

Purpose-built for speed, privacy, and breadth of format support.

  • Convert AVI to MKV in seconds

    Every AVI to MKV conversion runs on our servers, so your device stays fast and the output quality stays intact.

  • Fast, cloud-powered

    No queue, no waiting. Files are processed on high-performance servers and returned in seconds, even for large files.

  • Secure & private

    Encrypted in transit and never shared with anyone. Uploads are erased the moment your job completes, and results shortly after.

  • Free - no account needed

    Convert without creating an account - no credit card, no trial clock. Sign in only if you want history and higher daily limits.

Developer API

Convert AVI to MKV via API

Automate AVI to MKV conversions in three steps: create a job, upload your file, then poll for the result.

Replace YOUR_API_KEY with your RunConvert API key. Get your free API key at runconvert.com/api.

# 1. Create job
curl -X POST https://api.runconvert.com/v3/jobs \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "tag": "avi-to-mkv",
    "tasks": {
      "upload-file": {
        "operation": "import/upload"
      },
      "convert": {
        "operation": "convert",
        "input": "upload-file",
        "output_format": "mkv"
      },
      "export-result": {
        "operation": "export/url",
        "input": "convert"
      }
    }
  }'

# 2. Upload your file (use upload_url from the response)
curl -X PUT "$UPLOAD_URL" --upload-file input.avi

# 3. Poll for result
curl https://api.runconvert.com/v3/jobs/$JOB_ID?include=tasks \
  -H "Authorization: Bearer YOUR_API_KEY"

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