Convert FLV to MKV Online
Effectively dead β Flash Player was discontinued in 2020, and no modern browser supports FLV natively. Converting to MKV gives you a key advantage: the most flexible container: unlimited audio tracks, subtitle formats (srt, ass, pgs), chapter markers, and attachment files in a single open-standard file. MKV is best for archiving high-quality video with multiple audio tracks, subtitle streams, and chapter markers in one file.
Why Convert FLV to MKV?
Effectively dead β Flash Player was discontinued in 2020, and no modern browser supports FLV natively β converting to MKV overcomes this by providing the most flexible container: unlimited audio tracks, subtitle formats (srt, ass, pgs), chapter markers, and attachment files in a single open-standard file
MKV is the right choice when you need to: archiving blu-ray rips with original audio tracks (dts-hd, truehd) and subtitle streams
Gain broader compatibility β MKV works with VLC, MPC-HC, mpv, Plex, Kodi, Jellyfin; partial support on Android and some smart TVs
Your FLV files were created for converting archived flv files from early youtube downloads to modern mp4, but now you need a format suited to different workflows
FLV vs MKV β Format Comparison
Flash Video (.flv)
Matroska Video Container (.mkv)
How to Convert FLV to MKV
Upload your FLV file
Drag your .flv file onto the upload area or click to browse. We accept FLV files up to 1 GB.
Choose MKV as output format
Select .mkv (Matroska Video Container) from the format list. Configure any format-specific settings to match your requirements.
Convert and download
Click Convert and wait for processing. Your MKV file will be ready to download in seconds. The result is optimized for archiving high-quality video with multiple audio tracks, subtitle streams, and chapter markers in one file.
Frequently Asked Questions
Is the FLV to MKV conversion lossless?
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When both formats support lossless data, the conversion preserves all content. Container-agnostic: supports any codec (H.264, H.265, AV1, VP9) at any quality level.
How large will my MKV file be compared to the original FLV?
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FLV files are typically 5 MB β 1 GB, while MKV files are typically 50 MB β 30 GB. The actual size depends on content complexity and any quality settings you choose.
What software can open the converted MKV file?
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MKV is compatible with: VLC, MPC-HC, mpv, Plex, Kodi, Jellyfin; partial support on Android and some smart TVs.
What is the maximum file size I can convert?
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PureConverter accepts FLV files up to 1 GB. Your files are processed securely and deleted from our servers after conversion.
What's the difference between FLV and MKV?
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FLV (Flash Video) is best for playing legacy flash video content from the pre-html5 era of web video. MKV (Matroska Video Container) is best for archiving high-quality video with multiple audio tracks, subtitle streams, and chapter markers in one file. Key tradeoff: FLV's advantage is extremely small file sizes for its era, with fast seeking and low-latency streaming capabilities, while MKV's advantage is the most flexible container: unlimited audio tracks, subtitle formats (srt, ass, pgs), chapter markers, and attachment files in a single open-standard file.
Pro Tips for FLV to MKV Conversion
Review the output MKV file to ensure all formatting and content transferred correctly from your FLV source
Keep a backup of your original FLV file β while our conversion is reliable, having the source is always recommended
MKV works especially well for: storing anime with multiple subtitle tracks (soft-subs) for different fan translations
Did you know? Matroska is named after Russian nesting dolls (ΠΌΠ°ΡΡΡΡΠΊΠ°) because the format is based on EBML, which nests data structures inside each other like layers of a doll.
Ready to Convert?
Upload your FLV file above and get your MKV in seconds. Free, fast, and secure.