Is my file uploaded when converting FLV to MP4?

No. The conversion runs entirely in your browser. The file never leaves your device, there is no server to upload to, and the page works offline once loaded.

Is FLV to MP4 conversion free?

Yes, with no account, no watermark and no file limit per day. frogConvert is open source and there is no server cost to recover, because your device does the work.

How large a file can I convert?

Up to 2 GB for a single file, 500 MB total per batch, and 300 files at once. The practical limit is your device's memory, since everything is processed locally.

Convert FLV to MP4

Rescues video from the retired Flash format into MP4.

Convert FLV to MP4 →

Runs on: FFmpeg, compiled to WebAssembly, running in this tab
Steps: Direct, a single conversion
Input: .flv · video/x-flv
Output: .mp4 · video/mp4
Uploads: None. The file never leaves your device.

What to expect

FLV usually carries old, low-bitrate encodes. Converting preserves what is there but cannot improve it.

Why convert FLV without uploading

Most online converters take your file, send it to their servers, convert it there and hand back a download link. That means your document sits on someone else's disk, subject to their retention policy and their breaches. It also means you cannot use them offline, and cannot use them at all for anything confidential.

frogConvert does the conversion in the page itself, with FFmpeg compiled to WebAssembly. There is no upload step because there is no server. You can disconnect from the network and it still works.

About the formats

FLV

Flash Video, the format that carried web video until Flash was retired in 2020. Effectively legacy, and converting out of it is the normal reason to encounter one. More about FLV files.

MP4

The default video container almost everywhere, normally holding H.264 video and AAC audio. Its ubiquity, not its technical merit, is the reason to choose it. More about MP4 files.

Common questions

Is my file uploaded when converting FLV to MP4?: No. The conversion runs entirely in your browser. The file never leaves your device, there is no server to upload to, and the page works offline once loaded.
Is FLV to MP4 conversion free?: Yes, with no account, no watermark and no file limit per day. frogConvert is open source and there is no server cost to recover, because your device does the work.
How large a file can I convert?: Up to 2 GB for a single file, 500 MB total per batch, and 300 files at once. The practical limit is your device's memory, since everything is processed locally.
What is lost converting FLV to MP4?: FLV usually carries old, low-bitrate encodes. Converting preserves what is there but cannot improve it.