Convert
Convert FLV to MP4
Free, in your browser, with no watermark and no signup. Both are video files; this changes how the video is packaged and encoded.
Why you have a FLV file
FLV is the Flash video format, and Flash has been dead since 2020. If you have FLV files they are almost certainly old downloads or archived stream recordings, and essentially no current player, editor or upload form will touch them.
What the conversion actually does
The conversion pulls the video and audio out of the Flash container and re-encodes them into H.264 and AAC inside an MP4, which is the difference between a file nothing opens and a file everything opens.
Worth knowing first
FLV was usually encoded at low bitrates for slow connections, so the source quality is genuinely poor. Converting makes the file usable and archivable; it cannot make it look good.
How to convert FLV to MP4
- 01
Add your FLV file
Drop it in, or pick it from your device. Free uploads go up to 1 GB per file.
- 02
Choose MP4
Pick the output format from the list. Queue several files of the same type to batch them.
- 03
Download
Watch progress live, then download the result. No watermark, on any plan.
Other conversions
Frequently asked
How do I convert FLV to MP4 for free?
Open the GrumpTools File Converter, add your FLV file, choose MP4 as the output and download the result. It runs in the browser, output is never watermarked, and free uploads go up to 1 GB per file.
Does converting FLV to MP4 reduce quality?
FLV was usually encoded at low bitrates for slow connections, so the source quality is genuinely poor. Converting makes the file usable and archivable; it cannot make it look good.
Can I convert several FLV files at once?
Yes. Queue multiple files of the same type and convert them in one batch, then download them individually or all at once.