FLV to MKV — Lossless & Fast Online Converter
Convert FLV to MKV online for free — lossless remux — streams are copied, not re-encoded. Runs entirely in your browser, files are never uploaded, no watermark and no sign-up. Supports batch conversion; drop multiple files at once.
The FLV → MKV converter workspace runs on the main tool page — same local engine, same privacy. English workspace is on the way.
Open FLV to MKV converterHow it works
- 1Open the converter and drop your FLV file — or several at once for batch conversion.
- 2The engine reads your file locally: streams are copied into the MKV container without re-encoding.
- 3Download the finished MKV file. Nothing was uploaded at any point.
FAQ
Is the FLV to MKV conversion lossless?
Yes. FLV and MKV share compatible streams, so the converter remuxes them without re-encoding — quality is bit-identical and it takes seconds.
Do I need to install anything?
No. The converter runs on WebAssembly inside your browser. Nothing to install, no account required.
Are my files uploaded anywhere?
Never. Files are read with the browser File API and processed on your own device. The page even works offline once loaded.
Related converters
ZMQ Tools — https://www.zhuanmaqi.com/en/convert/flv-to-mkv