Is this AVI to MKV converter really free?

Yes. Up to 5 files at a time, no signup, no catch. The free tier adds a small watermark to image output — Pro ($9.99/mo or $49/yr) removes it, raises the file size limit to 500 MB, and unlocks unlimited batch conversion.

Are my files uploaded to a server?

No — and you can verify it yourself. Open DevTools → Network tab, then convert a file. You'll see zero upload requests. Everything runs right in your browser. We never see your files.

How long does conversion take?

Usually 1–3 seconds for a typical file. The very first conversion on a fresh page load may take 5–20 seconds while the converter engine loads — after that it's instant. Your CPU does all the work locally.

What is the file size limit?

Free: up to 10 MB per file, 5 files per batch. Pro: up to 500 MB per file, unlimited batch. If you're working with large videos or RAW photos, Pro is built for that.

Can I batch convert multiple AVI files at once?

Yes — drop multiple files at once (or Ctrl/Cmd+click to select them) and they all convert in parallel. Free accounts handle up to 5 files per batch; Pro has no limit.

How large can my video files be?

Free accounts support files up to 10 MB — enough for short clips and GIFs. Pro raises that to 500 MB, which covers most 1080p videos. For files over 1 GB, a native app like HandBrake will be faster.

Will the video lose quality during conversion?

When only the container changes (e.g., MKV → MP4 where both use H.264), there's zero quality loss — it's a lossless rewrap. When the codec changes, we encode at CRF 23, which is near-transparent for most content.

How private is this converter?

Completely private — by design, not policy. There is no upload endpoint. Files are processed right inside your browser tab and disappear the moment you close it. We collect only anonymous page-view counts; your file content is never seen or stored.

AVI to MKV — Free, Modern Container, No Upload

How to convert AVI to MKV online

1
Drop your AVI file
Drag and drop your Audio Video Interleave file onto the converter, or click to browse your files. You can select up to 5 at once. Nothing leaves your device — conversion happens right here in the browser.
2
Hit Convert — it happens locally
Click Convert and watch it go. There's no upload, no server queue, no waiting. The converter runs Audio Video Interleave → Matroska Video entirely in your browser tab. Most files finish in 1–3 seconds.
3
Download your MKV
Your Matroska Video file is ready. Click Download, or grab a ZIP if you converted a batch. Close the tab and everything disappears — no copies kept anywhere.

AVI vs MKV: format overview

AVI

Audio Video Interleave

Microsoft · 1992

Compression: lossy
Transparency: No

✓ Universal Windows compatibility
✓ Simple container format — widely supported
✗ Large file sizes (minimal compression)

MKV

Matroska Video

Matroska.org · 2002

Compression: lossy
Transparency: No

✓ Supports virtually any codec combination
✓ Multiple audio tracks and subtitles per file

AVI magic bytes: 52 49 46 46 xx xx xx xx 41 56 49 20

MKV magic bytes: 1A 45 DF A3

Why convert AVI to MKV?

AVI is a container format from 1992 that has significant limitations by modern standards. It does not natively support variable frame rate video, which causes sync problems with screen recordings and modern smartphone video. AVI files do not support multiple audio tracks, subtitle streams, or chapter markers. When you have an AVI video library and want to manage it in a media server like Plex or Jellyfin, the lack of these features makes AVI files harder to organize and less capable than modern alternatives.

MKV is the container format that Plex, Jellyfin, Kodi, and most modern media center applications prefer. It handles H.264 and H.265 video, supports embedded subtitle tracks in multiple languages, allows multiple audio tracks for different language dubs, and stores chapter information for easy navigation. Archiving a video collection in MKV with proper metadata, subtitles, and audio tracks makes it significantly more useful and organized than the same content in AVI.

For many AVI files, the conversion to MKV can be performed as a lossless remux if the video codec inside the AVI is already H.264 or another codec that MKV supports. In that case, the video stream is simply moved from the AVI container to the MKV container without any re-encoding, meaning zero quality loss and very fast processing. If the AVI contains an older codec like DivX or Xvid, a full re-encode to H.264 or H.265 is necessary, which takes longer but produces a much more compatible and efficient output.

Quality & file size: AVI to MKV

Typical file sizes: AVI 200–600 MB → MKV 200–800 MB.

Both AVI and MKV use lossy compression. We transcode at high quality settings (equivalent to MKV's recommended web quality) to minimize generational loss.

Color depth: AVI supports standard color, MKV supports standard color.

Transparency: AVI does not support transparency. MKV does not support transparency — transparent areas become solid white.

Frequently asked questions

Privacy: how FormatDrop handles your files

Your AVI files are converted 100% inside your browser. They are never uploaded to our servers, never stored, and never seen by anyone other than you. This isn't a privacy policy claim — it's an architectural guarantee: our server has no endpoint that receives file bytes.