Free tool

MP3 to FLAC converter a lossless file from any MP3.

Drop MP3 files and download FLAC versions for a library, a hi-fi player or an editor that only takes lossless input.

MP3 to FLAC converter at a glance

content.win converts audio a whole folder at a time, with no daily cap and no file-size wall.

Works with
MP3, WAV, M4A and AAC, OGG and Opus, FLAC, AIFF, and the sound of an MP4, MOV or WebM. Several at once.
Comes back as
MP3, WAV, M4A, OGG or FLAC, the full length, named after the original.
Runs
In your browser.
Limits
No daily limit and no cap on how many files.
Price
Free. No account, no watermark.

How to convert MP3 to FLAC

  1. Drop the MP3 files in. One or a folder.
  2. Nothing to set. FLAC is lossless, so there is no bitrate to choose.
  3. Download the FLACs. The full length of each, named after the originals.

What to expect

No lost detail comes back
FLAC stores exactly what the MP3 decoded to. It does not restore what the MP3 left out; it stops any further loss from here on.
Why do it anyway
Some players, editors and tagging tools accept only FLAC or WAV. FLAC is the smaller of the two and carries tags.
Size
Expect the FLAC to be five to eight times the MP3's size.

Questions people ask

Does MP3 to FLAC improve the sound?

No. The FLAC sounds exactly like the MP3. It is lossless from this point on, nothing more.

Why is the file so much bigger?

FLAC keeps every sample; MP3 threw most of them away. The size reflects that.

When should I use WAV instead?

When the destination asks for WAV specifically. Otherwise FLAC is smaller and holds tags.

Can I convert several at once?

Yes. Drop the folder and one button downloads every FLAC.