How do I convert FLV to MP3?

Add your FLV file to the upload area above, then press Convert. The MP3 file downloads straight to your device. You do not need an account, and there is no watermark.

Are my files uploaded to a server?

No. This conversion runs entirely inside your browser using WebAssembly, so the file never leaves your device — you can even disconnect from the internet after the page loads and it will still work.

Does converting to MP3 reduce quality?

MP3 uses lossy compression, so some data is discarded. At the default quality the difference is very hard to see or hear; raise the quality setting if you need to be certain, at the cost of a larger file.

How large a file can I convert?

Up to 512 MB per file for this conversion. Because the work happens in your browser, the practical limit is your device's memory — larger files work on a desktop with plenty of RAM and may fail on an older phone.

Can I convert several files at once?

Yes. Add as many as you like and press Convert All. Each file is processed independently, so one failure does not stop the rest, and you can download everything together as a ZIP.

Can I use this on my phone?

Yes. FileTools360 works in mobile browsers on iOS and Android, including choosing files straight from your camera roll. Very large videos may run out of memory on a phone — those are better converted on a laptop.

VideoAdjustable qualityRuns in your browser

FLV to MP3 Converter

Turn FLV files into MP3 in a couple of clicks. Obsolete Flash container. Convert to MP4 to keep it playable. The universal lossy audio format. The output is re-encoded, so quality depends on the settings you choose.

On your deviceNever uploadedGone when you close the tabHow this works

Drop your files here

FLV files (.flv) · up to 512 MB each

or paste files from your clipboard

Ready when you are

Drop a FLV file above and FileTools360 will turn it into MP3 — right here on your device, without uploading anything.

⌘K to search converters

How to use it

1
Add your FLV files
Drag them onto the upload area, choose them from your device, or paste them from your clipboard. You can queue several at once.
2
Adjust the settings if you want to
The defaults suit most people. Open Advanced to control bitrate, sample rate and channels and start and end times.
3
Convert and download
Press Convert. Everything happens on your own device — nothing is uploaded. Download files one by one, or grab them all as a ZIP.

FLV and MP3 explained

FLV was the container behind Flash video, which dominated online video until browsers removed Flash support entirely at the end of 2020. Nothing plays FLV natively today.

MP3 is the lossy audio format that made digital music portable. Its patents expired in 2017, which is part of why it remains ubiquitous — anyone can implement it freely.

Where FLV files come from: Video downloaded or archived from the web before roughly 2015.
Where MP3 is used: Music libraries, podcasts and voice recordings.

FLV vs MP3

The two formats solve different problems, which is why converting between them involves trade-offs rather than a straight upgrade.

FLV compared with MP3
Property	Source	Target
Compression	Container (depends on codec)	Lossy
Animation	Yes	—
Introduced	2002	1993
Browser support	Effectively dead — nothing plays it natively any more.	Plays absolutely everywhere.

FLV is stronger at: Historically small files for their era.
MP3 is stronger at: Plays on absolutely everything, including old hardware. Small files. No licensing constraints since 2017.

Why convert FLV to MP3?

This is not really a format swap — it is extraction. An FLV file carries a video track and an audio track side by side, and converting to MP3 discards the picture and keeps the sound. People do it to turn a lecture, interview, podcast recording or music video into something they can listen to without the video, at a fraction of the file size.

FLV limitations that prompt the switch: Effectively dead — no browser or modern player supports it. Low quality ceiling by current standards.
What you give up: Lossy — discarded detail cannot be recovered. Beaten on quality-per-byte by AAC and Opus.

Does converting FLV to MP3 reduce quality?

FLV stores your data exactly; MP3 does not. Some detail is discarded permanently in exchange for a much smaller file, which is usually the right trade for sharing and publishing. Keep your FLV original if it is the only copy — the conversion cannot be undone.

Converting MP3 to a lossless format like FLAC does not restore quality. It produces a larger file containing exactly the same degraded audio.