18 Best AVI to MKV Converters in 2026 (Free and Paid)

AVI to MKV is the archival conversion. AVI is the legacy 1990s Windows container; MKV is the modern open container designed to hold everything AVI cannot — multiple audio tracks, subtitles, chapter markers, attached fonts, and proper metadata. The conversion is almost always a remux with no re-encoding required, so it is instant and lossless. The killer feature is that you can finally add subtitles, chapters, and multi-language audio to an old AVI archive that started as a single-track file. This guide compares 18 AVI to MKV converters in 2026.

AVI → MKV is the cleanest container conversion in this whole series — the AVI's Xvid or DivX video transfers bit-identical into MKV in seconds.

Quick Picks for AVI → MKV

• Best CLI: FFmpeg with -c copy.
• Best GUI for adding tracks: MKVToolNix.
• One-shot: How to Convert.

One-shot: AVI to MKV converter.

1. How to Convert (I built this one)

Drop AVIs in, pick MKV, hit convert. Remux by default. Local.

Pricing

• One-time purchase; free web demo for single-file conversions.

2. FFmpeg

ffmpeg -i input.avi -c copy output.mkv

Batch:

for f in *.avi; do ffmpeg -i "$f" -c copy "${f%.avi}.mkv"; done

Adding an external SRT subtitle during the remux:

ffmpeg -i input.avi -i subtitles.srt -c copy -c:s srt output.mkv

Pricing

• Free, open source.

3. MKVToolNix

The reference Matroska toolkit. Drag AVI into mkvmerge GUI, add SRT subtitles, set chapter markers, set language tags, save MKV. Indispensable for archival library work.

Pricing

• Free, open source.

4. HandBrake

Always re-encodes. Useful if you also want to convert the legacy Xvid/DivX video to H.264 for smaller files.

Pricing

• Free, open source.

5. Shutter Encoder

FFmpeg GUI with remux option.

Pricing

• Free.

6. VLC

Media → Convert / Save → MKV.

Pricing

• Free, open source.

7. Permute (Mac)

Mac-native converter.

Pricing

• One-time purchase.

8. Any Video Converter

Consumer converter with MKV output.

Pricing

• Freemium.

9. Wondershare UniConverter

Full media suite.

Pricing

• Paid.

10. Movavi Video Converter

Beginner-friendly paid converter.

Pricing

• Paid.

11. Adapter

Free Mac and Windows tool.

Pricing

• Free.

12. Prism Video Converter

Simple NCH paid tool.

Pricing

• Free home; paid commercial.

13. Kdenlive

Free open-source video editor with MKV render.

Pricing

• Free, open source.

14. CloudConvert

Web AVI → MKV.

Pricing

• Free tier; paid above.

15. Convertio

Web AVI → MKV.

Pricing

• Free with caps; paid above.

16. Online-Convert

Web converter with codec options.

Pricing

• Free with limits; paid above.

17. FreeConvert

Web converter.

Pricing

• Free with caps; paid above.

18. Zamzar

Long-running web converter.

Pricing

• Free with daily limits; paid above.

How to Choose

• Quick remux: FFmpeg -c copy or How to Convert.
• Adding subtitles or chapters: MKVToolNix.
• Re-encode to modern codec: HandBrake.
• Archive batch: FFmpeg in a script.

Final Thoughts

AVI → MKV is the right archive step for legacy video. FFmpeg -c copy moves the video and audio losslessly in seconds. MKVToolNix adds the metadata, subtitles, and chapter markers that AVI never supported. Skip web tools for big archive batches — local processing finishes in a fraction of the time.