FLAC to MP3 Converter

Encode your lossless FLAC library into MP3 for a phone, a car or a player that will not read FLAC, at up to 320 kbps and without the files leaving your machine.

The converter is ffmpeg compiled to WebAssembly. It downloads once (30 MB) when you pick your first file, then stays in your browser cache.

A higher bitrate keeps more detail and costs more bytes. 192 kbps is transparent for most music on ordinary gear, 128 is plenty for speech, and 320 is the practical ceiling for MP3.

Your file is processed by your own browser and never uploaded. The engine itself is a one-time 30 MB download the first time you use it, and after that it comes out of your browser cache.

How to use FLAC to MP3

  1. 1Drop your .flac files onto the box above, or click to pick them. A whole album at once is fine.
  2. 2Choose a bitrate. 320 kbps is the usual answer when the FLAC is your archive copy.
  3. 3Play a track to confirm, then download. An album comes out as a single .zip.

Why this conversion is the good kind

Everything on this site that touches lossy audio comes with a caveat about generation loss. This page mostly does not, because FLAC is lossless. The compression it applies is exactly reversible, so what the encoder sees when you convert FLAC to MP3 is the original waveform, not the residue of somebody else's compression.

That makes this a first-generation encode, the best case for MP3. At 320 kbps the result is very hard to distinguish from the source on real playback equipment, and the reason to be generous with bitrate here is precisely that your source is perfect: there is no point starting from a pristine master and then being stingy.

Keep the FLAC

The whole point of a lossless archive is that you can regenerate lossy copies whenever the situation changes. A new phone, a car with a different format list, a streaming upload spec, a codec that did not exist when you ripped the disc. All of those are trivial if you still have the FLAC, and impossible if you do not.

So treat the MP3 as disposable and the FLAC as the thing you back up. Deleting the lossless original to save space is the one mistake in this workflow that cannot be undone later.

What to expect from the file

Three to four times smaller, typically. FLAC has already removed the easy redundancy losslessly, so it is not starting from WAV-sized bytes. The sample rate is preserved, including high-resolution files: a 96 kHz FLAC produces a 96 kHz MP3, though whether that helps anything is a separate argument.

Text tags survive. Cover art does not. Everything runs in your browser, on your own machine, using ffmpeg compiled to WebAssembly and cached after the first file.

Frequently asked questions

Is this the right direction to convert?
Yes, and it is the intended one. FLAC is an archive format and MP3 is a delivery format. Keep the FLAC, make MP3 copies from it for the devices that need them, and re-make those copies whenever you like. What you should not do is delete the FLAC afterwards, because the MP3 cannot be turned back into it.
Which bitrate for music?
320 kbps when you are encoding from lossless and storage is not tight, which is most of the time now. 256 kbps is nearly indistinguishable and 20 percent smaller. Below 192 kbps you start hearing it on cymbals and reverb, which is a shame given that your source was perfect.
How much smaller does it get?
Roughly three to four times. FLAC already compresses losslessly to about half of WAV, so a 30 MB FLAC track typically becomes an 8 to 10 MB MP3 at 320 kbps.
Do the tags come across?
Title, artist, album and similar text tags do. Embedded cover art does not, because the artwork sits in the file as an image stream and this tool keeps only the audio. Most music players will find album art by other means, and a tag editor can re-attach it if not.
Can I convert a whole album at once?
Yes. Drop the whole folder's worth of files and they are processed one after another, then offered as a single .zip. They run sequentially rather than in parallel on purpose, because several simultaneous encodes compete for memory and are what kills a browser tab on a phone.

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