AVI to MKV Converter

Move AVI video into MKV, an open container that holds several audio tracks and subtitles. Free, in your browser, with no signup and no watermark.

Select AVI file →

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We support most file types including: MP4, MOV, WEBM, AVI, MP3, WAV, PNG, JPEG, GIF, MKV, PDF, FLAC, TIFF!

EchoWave is used by creators, marketers, educators, and businesses to convert and edit media online.

Updated June 2026

AVI is an aging Windows container that is limited in what it can carry, while MKV is an open Matroska container that holds almost any codec plus several audio tracks and subtitle tracks in one file. Converting AVI to MKV is a good fit for movies and archives with multiple languages or captions. It is free, runs in your browser, and adds no watermark.

Free, no sign-upNo account, no trial

Runs in your browserNothing to install

Works on every devicePhone, tablet, laptop

No watermarkClean output, every time

How it works

How to convert AVI to MKV

1
Upload your AVI
Drag your AVI onto the converter or pick it from your device. Nothing to install.
2
Choose MKV and convert
Select MKV as the output and start. Free, with no sign-up and no watermark.
3
Download your MKV
Save the finished MKV, or open it in the editor to trim, crop, or resize it first.

Try it

Estimate your MKV

Pick a video bitrate and a length to see the MKV file size before you convert.

Video bitrate

Length5 min

1 min30 min

Estimated MKV size183MBSharp 1080p

An estimate. Real size varies with resolution, frame rate, and how much the picture moves.

The formats

AVI vs MKV

AVI

Audio Video Interleave

A legacy Microsoft video container

Type: Legacy video container
Holds: Older codecs like DivX or Xvid with MP3 or PCM audio
Typical size: Large for the quality it gives
Plays on: Windows and VLC, patchy on phones

Best for:Playing older Windows video files

MKV

Matroska Video

An open container that holds almost anything

Type: Open video container
Holds: Almost any codec, plus several audio and subtitle tracks
Typical size: Large, depends on the codec inside
Plays on: VLC and most modern players, less on default phone apps

Best for:Movies with multiple audio tracks and subtitles

Will it lose quality?

When the codecs already match MKV, the converter can change the container without re-encoding, so the picture stays identical.
When the video has to be re-encoded for MKV, a high bitrate keeps it visually close to the AVI.
Converting cannot add detail the AVI never had. The output is at best as good as the source.

Use cases

What people use it for

Play anywhereMake a clip your device supports

Video editorsGet footage your software accepts

Web videoUse a format browsers play

CourseworkHand in a standard video file

SharingSend a clip people can open

Troubleshooting

If something looks off

The MKV will not play

Some players are picky about codecs. Try it in VLC, which opens almost anything, or convert again and let the converter re-encode the video.

The file got larger

A format change can shift the size, and re-encoding at a high bitrate adds overhead. Lower the bitrate or trim the clip for a smaller file.

Audio and video drift out of sync

Re-download the source and convert again. If a long recording drifts, splitting it into shorter pieces usually fixes the sync.

FAQ

AVI to MKV questions

Is the AVI to MKV converter free?

Yes. EchoWave converts AVI to MKV with no signup, no file-count limit, no trial, and no watermark. Upload your AVI, convert it, and download the MKV from your browser.

Why convert AVI to MKV?

MKV is an open container that can hold multiple audio tracks, multiple subtitle tracks, and almost any codec in a single file. That makes it a better home than AVI for multilingual movies, archived footage, and rich video collections.

How do I convert AVI to MKV?

Upload your AVI, choose MKV as the output format, and start the conversion. When it finishes, download the MKV or open it in the editor to trim, crop, or resize it first.

Will converting AVI to MKV lose quality?

When the video codec already suits MKV, the converter can change the container without re-encoding, so the picture stays identical. If a re-encode is needed, a high bitrate keeps the result close to the source, and converting never adds detail the AVI did not have.

Can an MKV hold subtitles and several audio languages?

Yes. MKV is designed to carry multiple subtitle tracks and multiple audio tracks side by side, so viewers can switch language or captions in a player like VLC. The tracks available depend on what your source AVI and any added files contain.

What plays MKV files?

VLC and most modern desktop players open MKV without setup, and many smart TVs and media boxes support it too. Default phone players are patchier, so convert to MP4 if you mainly watch on a phone.

Can I convert AVI to MKV on Mac and Windows?

Yes. The converter runs in any browser on macOS, Windows, Chromebook, and Linux, so you do not need MKVToolNix or a desktop converter installed. There is nothing to download and no account to create.

Does it work on iPhone and Android?

Yes. It runs in your mobile browser, so you can convert AVI to MKV on iPhone, iPad, and Android. For playback on the phone itself, a player like VLC opens MKV, or convert to MP4 instead.

Can I convert a big movie file or a batch of AVIs?

Yes. There are no file-count limits on these pages, so you can run your AVI files through one after another. Long movies are supported and simply take a little longer to upload and convert.

Is it safe to convert AVI to MKV here?

Repackaging an AVI into a Matroska MKV container needs no account and no tools like MKVToolNix set up on your machine. Our security page covers how your uploaded AVI and the resulting MKV, including any audio or subtitle tracks it carries, are handled.