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AVI MKV
File conversion

Convert AVI to MKV

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Verified by Adam B.· reviewed by FE Editorial ·updated Jun 24, 2026
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Is it possible to convert AVI to MKV?
Yes - AVI converts to MKV.

You can do it right here with our free converter - no sign-up, and your file is deleted right after.

The fastest path is the free converter above (files are deleted after converting) or ffmpeg -i input.avi -c copy output.mkv on the command line. The result is identical quality at nearly the same file size - remuxing is not a compression step.

Also to MKV: USM · TP · MPEG4

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Tested on macOS, Windows & Linux
Last verified Sep 2026

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Why convert AVI to MKV?

AVI cannot hold soft subtitle tracks, multiple audio streams, or chapters, while .MKV handles all of these natively. Most people remux rather than re-encode - they keep the existing video codec (DivX, Xvid, H.264) and gain the ability to attach selectable subtitles. MKV also stores variable frame-rate timing more accurately, which can fix sync drift present in some AVI files.

How to convert AVI to MKV

MKVToolNix OPEN-SOURCE

Add your .avi in MKVMerge GUI and click Start multiplexing - streams are copied without re-encoding by default.

HandBrake FREE

Open your .avi, choose an MKV container preset, and click Start Encode - HandBrake re-encodes the video, so conversion takes longer than a remux.

Freemake Video Converter FREE

Add your .avi, select MKV as the output format, and click Convert.

Command line - FFmpeg CLI

Run ffmpeg -i input.avi -c copy output.mkv to remux instantly without re-encoding.

Programs that convert AVI

Miro Video Converter
HandBrake
Any Video Converter FREE
Aimersoft iTransfer for Windows
AviDemux
ConvertXtoDVD
Free Studio
Freemake Video Converter

About these formats

.AVI Audio Video Interleave

An AVI file is a video container created by Microsoft in 1992. To open one, use VLC media player - it includes the DivX/Xvid codecs old AVIs need and works on Windows, Mac, Linux, Android…

Open .AVI details →
.MKV Matroska Video

An MKV file is a Matroska multimedia container that holds video, multiple audio tracks, subtitles and chapters in one file. Open it for free with VLC media player, or on Windows 11 with the…

Open .MKV details →

Quality & what to watch

  • Remuxing with -c copy (FFmpeg) or MKVToolNix copies video and audio data unchanged - quality and file size stay the same.
  • MKV supports soft subtitle tracks that AVI cannot; embed an .srt alongside your video by passing it as a second input to FFmpeg or adding it in MKVToolNix before muxing.
  • Re-encoding tools like HandBrake can shrink the file but take much longer and reduce quality - only use them if a smaller file is the goal.

Frequently asked questions

Does converting AVI to MKV reduce quality?
No, if you remux using FFmpeg with -c copy or MKVToolNix - both copy the encoded streams without modification. Quality loss only occurs if you explicitly re-encode.
Will the MKV file be smaller than the AVI?
Not from remuxing - video and audio data is identical, so file size stays nearly the same. To shrink the file you must re-encode to H.264 or H.265, which is a separate step.
Can I add subtitles during conversion?
Yes - FFmpeg accepts a subtitle file alongside the AVI input, and MKVToolNix lets you add subtitle tracks before muxing, embedding them as selectable tracks in the output .mkv.
Do AVI files larger than 2 GB work?
Yes - large AVI files using the OpenDML extension are read correctly by FFmpeg and produce a properly seekable .mkv.