How do I convert AVI to Matroska (MKV)?

Upload your AVI file using the box above, confirm Matroska (MKV) as the output format, then select Convert. The converted file is ready to download as soon as processing finishes — usually in a few seconds.

Is converting AVI to MKV free?

Yes, and there is nothing to sign up for. Every conversion route is free on every plan — paying raises limits such as file size and how many conversions you get, and removes advertising. It never unlocks a format, adds a watermark or degrades the output.

Will the quality change when converting to Matroska (MKV)?

MKV uses lossy compression, so some data is discarded to keep the file small. The default quality setting is tuned to be visually or audibly transparent for most material, and you can raise it in the conversion settings.

What happens to my file afterwards?

The uploaded file is deleted as soon as the conversion completes, and the converted file is removed automatically once its retention window ends. Download links are signed and expire within minutes.

avimkv

Convert AVI to Matroska (MKV)

Free online converter for AVI files. Flexible container for high-quality video. Nothing to install, no watermark, and every file is deleted automatically.

Drag and drop your files

Upload a AVI file to convert it to Matroska (MKV). Up to 3 files at once, 100 MB each.

Free · up to 3 files · 100 MB each · files deleted automatically after 1 hour.

About AVI and MKV

AVI .avi

A Microsoft container from 1992. Still readable everywhere, but it predates modern streaming, subtitles and variable bitrate audio.

Good for

Opens in very old software
Simple, well-understood structure

Trade-offs

Much larger than MP4 for the same quality
No native subtitle support
Poor handling of variable bitrate audio and modern codecs

video/x-msvideo

Matroska (MKV) .mkv

Matroska: an open container that will hold almost any combination of video, audio, subtitle and chapter tracks in one file.

Good for

Unlimited tracks — multiple languages, subtitles, chapters
Codec-agnostic, so it holds nearly anything
Open, well documented, and resilient to damage

Trade-offs

Browsers will not play it natively
Many TVs and phones refuse it — the usual reason to convert
Being a container, contents vary wildly file to file

video/x-matroska

AVI and MKV side by side

AVI compared with Matroska (MKV)
	AVI	MKV
Compression	Container — usually older codecs	Container — any codec
Transparency	No	Depends on codec
Typically used for	Legacy video files	Archival video, multi-language releases

What changes when you convert AVI to MKV

AVI and MKV are unrelated containers

AVI is built on RIFF, Microsoft's chunk format from 1992. MKV is Matroska, an open container that accepts almost any codec. A container is a box, not a compression method: what decides how a video looks and how large it is, is the codec stored inside, and these two boxes accept different ones.

This is a re-encode, not a repackage

Some tools can move a stream into a different container untouched when the codecs happen to line up. We do not — every job here is decoded and encoded again, so the conversion takes time in proportion to the length of the file and costs a small amount of quality even where a repackage would have been possible. In exchange the output is predictable: it plays everywhere, rather than inheriting whatever the source happened to contain.

What your MKV will contain

The output is H.264 video with AAC audio — Matroska imposes no codec restrictions, so the choice here is for compatibility rather than because the container demands it. What Matroska adds is room — multiple audio tracks, subtitles and chapters all have a proper place in it, which is why it is the format of choice for archiving a film.

Other AVI conversions

Other ways to get Matroska (MKV)

Worth reading next

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