Is the FLV to MP4 conversion free?

Yes. Atlas Convert is completely free, no account needed, no watermarks, no ads.

Are my files uploaded to a server?

Most conversions run entirely in your browser using WebAssembly (ffmpeg.wasm, fflate, canvas). Only when a conversion genuinely requires server-side software (for example PDF↔DOCX or WMV target) is the file sent to our backend, processed in an ephemeral temporary directory, and deleted within seconds.

What does MP4 look like compared to FLV?

Atlas Convert preserves the content faithfully when converting from FLV to MP4, but the underlying capabilities of each format differ — for example, format-specific features such as transparency, animation, vector data, or document layout may behave differently in the output.

Convert FLV to MP4

Drop a FLV file below — Atlas Convert turns it into MP4 in seconds. Free, no signup, and runs locally in your browser for the highest privacy.

Drop your file here

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Step 1

Drop or pick your FLV file.

Step 2

We detect the format and convert to MP4 for you.

Step 3

Save the converted MP4 file to your device.

About FLV to MP4

FLV and MP4 are both common video formats. Atlas Convert handles the conversion using best-in-class open-source tools — running entirely in your browser whenever possible, falling back to our sandboxed backend only when a specific pair genuinely requires server-side processing.

•Files up to 50 MB are supported.
•Most conversions never leave your browser — your file stays private.
•Free, no account, no watermarks, no ads.