Convert AVI to MKV
Last updated: June 1, 2026To convert AVI to MKV, drop your AVI file into the converter above, then download the MKV result. It's free, needs no sign-up, and there's no watermark. Conversion runs in your browser with on-device FFmpeg, so your files never leave your device.
Why convert AVI to MKV?
Repackaging an AVI into MKV upgrades a rigid 1992 Microsoft container into Matroska, the flexible open format that holds unlimited audio tracks, soft subtitles, and chapter markers in one file. This converter runs FFmpeg compiled to WebAssembly directly in your browser, so your AVI is processed on your own device and never uploaded to a server. It is completely free, with no sign-up, no watermark, and no file-size catch attached to an account.
- Your media player or smart TV chokes on an old AVI file (DivX/XviD codec or odd index), and rewrapping it as MKV makes it play smoothly in VLC, Kodi, Plex, or Jellyfin.
- You have a movie as a separate AVI plus an .srt subtitle file and want everything bundled into a single MKV with embedded soft subtitles and multiple audio tracks.
- You are archiving or organizing a library and prefer the modern, open Matroska container over legacy AVI for better metadata, chapter support, and future-proofing.
AVI vs MKV
AVI · Audio Video Interleave
AVI is an older Microsoft container. It's widely readable on desktops but produces large files and lacks modern features like streaming-friendly fast-start, so it's usually converted to MP4.
MKV · Matroska Video
MKV (Matroska) is a flexible open container that can hold many video, audio and subtitle tracks in one file. It's popular for archiving, but doesn't play natively in many browsers or on some TVs.
Need more options?
Video Converter
Convert video to MP4, WebM, MOV, MKV, GIF or MP3.
Open Video ConverterAVI to MKV — frequently asked questions
Will converting AVI to MKV reduce the video quality?
Changing the container itself does not touch the picture. When the streams inside your AVI can be carried straight into MKV, the video and audio are copied as-is, so there is no generational quality loss and the file size stays roughly the same. Any quality change only happens if a codec inside the AVI has to be re-encoded for compatibility.
Is my AVI file uploaded anywhere during conversion?
No. The entire conversion happens inside your browser tab using FFmpeg compiled to WebAssembly. Your file is read from your device, processed in your computer's memory, and the MKV is handed back to you for download. Nothing is sent to a server, which is why it works even on private or confidential footage.
Does the MKV keep my subtitles and multiple audio tracks?
MKV is built for exactly this. Unlike AVI, which is limited to a single video and audio stream, Matroska can hold many audio languages, soft subtitle tracks, and chapters in one file, so your tracks carry over into the MKV container.
How do I convert AVI to MKV?
Drop your AVI file (or several) into the converter, confirm MKV is selected as the output, click convert, then download the MKV file. The whole thing takes a few seconds.
Is this AVI to MKV converter free?
Yes — it's completely free with no watermark and no sign-up required.
Is it safe to convert AVI to MKV here?
Yes. Conversion runs on-device with FFmpeg compiled to WebAssembly, so your AVI file is never uploaded to a server.
Can I convert multiple AVI files at once?
Convert one AVI file at a time — finish one, then drop in the next.
Does it work on mobile?
Yes — the converter runs in any modern browser on phones, tablets and desktops.