Convert FLV to MKV
Convert FLV files to MKV locally, completely free and with maximum privacy.
Drag and drop your files here
or click to browse local files (large files supported, limited only by browser RAM)
Upload FilesPlatform Statistics
How to convert FLV to MKV
- Drop your .flv files above, or click Upload Files. You can add many files at once.
- MKV is already selected as the output. Open the settings (gear icon) to fine-tune the result.
- Click Convert All. FFmpeg runs inside your browser through WebAssembly; nothing is uploaded.
- Download your .mkv files as soon as each one finishes.
What to know about FLV to MKV conversion
- The video is re-encoded to H.264 video and AAC audio so it plays wherever MKV is supported, and odd frame sizes are adjusted automatically.
- You can change the resolution, frame rate, playback speed and quality (CRF) before converting.
FLV vs MKV
| Feature | FLV (Flash Video) | MKV (Matroska Video) |
|---|---|---|
| Codecs used by PureConverter | H.264 video and AAC audio | H.264 video and AAC audio |
| Best for | legacy Flash-based players and old streaming setups | movies with several audio and subtitle tracks |
| Opens in | VLC, mpv and most media players | VLC, mpv and most media players, Plex and most smart TVs |
FLV (Flash Video): A legacy streaming video container popularised by Adobe Flash Player.
MKV (Matroska Video): A flexible, open-standard video container format that can hold unlimited video, audio, picture, or subtitle tracks.
Conversion options
- Resolution: original, 1080p, 720p, 480p or 360p
- Frame rate and playback speed (0.5× to 2×)
- Quality presets or a custom CRF value, and lossless mode
- Audio bitrate, sample rate and channels
Frequently asked questions
Is it safe to convert FLV to MKV here?
Yes. Your files are processed entirely on your own device by WebAssembly code running in the browser. They are never uploaded, so nobody else can see them, and the converter keeps working even if your connection drops after the page loads.
Is there a file size limit?
There is no server-side limit. The only limit is the memory available to your browser, typically 1.5–4 GB on desktop computers.
Can I convert several FLV files at once?
Yes. Add as many files as you like; they are converted in parallel according to your device's CPU cores, and you can apply the same settings to all of them.
Related conversions
Need the opposite? Convert MKV to FLV.
Convert FLV to other formats
- FLV to MP4
- FLV to MP3
- FLV to WEBP
- FLV to GIF
- FLV to WAV
- FLV to MOV
- FLV to M4A
- FLV to FLAC
- FLV to WEBM
- FLV to AAC
- FLV to OGG
- FLV to OPUS
Convert other formats to MKV
- MP4 to MKV
- MOV to MKV
- WEBM to MKV
- AVI to MKV
- WMV to MKV
- M4V to MKV
- MPEG to MKV
- TS to MKV
- 3GP to MKV
- OGV to MKV
See every FLV converter and MKV converter, or browse the full converter directory.