What is a .flac file?
Free Lossless Audio Codec · Audio · Xiph.Org Foundation · 2001
FLAC compresses audio without losing a single bit, giving you CD-quality or better sound at roughly half the size of WAV. It is the favourite of audiophiles and music archives who want perfect copies that still save space.
What is a .flac file used for?
FLAC is lossless: decompress it and you get back exactly the original samples. That makes it ideal for archiving CDs and high-resolution audio.
Compared with WAV it saves around 40 to 60 percent of the space while staying bit-perfect, and it supports rich tags and cover art.
Support is now broad on desktops and Android, though Apple historically preferred its own ALAC. Converting to ALAC or MP3 covers those cases.
What opens a .flac file?
The .flac format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list.
Windows
- VLC
- foobar2000
- Media Player (Windows 10+)
macOS
- VLC
- Music (recent macOS)
Linux
- VLC
- Rhythmbox
Web
- Most modern browsers
Open a .flac file step by step
- Confirm the file really is a .flac. Drop it into the WhatFileType identifier, which reads its signature in your browser without uploading anything.
- On Windows, open it with VLC or foobar2000.
- On Mac, use VLC or Music (recent macOS).
- On Linux, try VLC or Rhythmbox.
- Still stuck? Convert the .flac to MP3, which opens more widely.
Why can't I open my .flac file?
Almost always because no installed app understands FLAC. Install one of the apps above, or convert the file to a format your existing software already reads. If double-clicking opens the wrong program instead of nothing at all, the file association is set to the wrong app rather than the file being broken.
The other possibility is that the file is not really a .flac at all. Drop it into the file identifier to check it by its bytes instead of its name. Nothing is uploaded.
How to convert a .flac file
You can convert a .flac file to MP3, WAV, ALAC, AAC.
FFmpeg converts FLAC to MP3 in one line: ffmpeg -i in.flac -q:a 0 out.mp3. That is the direction that works. FLAC to MP3 is lossy and one-way, so keep the FLAC as the archive copy.
What is the .flac file signature (magic bytes)?
A .flac file starts with the hex bytes 66 4C 61 43, which read as fLaC in ASCII. Programs identify FLAC by those bytes, not by the filename, so a renamed file still gives itself away.
These are the documented signatures for FLAC. For a full breakdown, see the FLAC file signature page.
| Hex signature | Offset | ASCII | Note |
|---|---|---|---|
| 66 4C 61 43 | 0 | fLaC | 'fLaC' |
See the full magic-numbers reference for every format.
Frequently asked questions
What is a .flac file?
FLAC compresses audio without losing a single bit, giving you CD-quality or better sound at roughly half the size of WAV. It is the favourite of audiophiles and music archives who want perfect copies that still save space.
Is FLAC better than MP3?
FLAC is lossless so it is technically superior, but the files are much larger. For casual listening on the go, MP3 or AAC is more practical.
Comparisons
Related formats
Sources
Details on this page were checked against authoritative references. How sources are ranked and what is deliberately left out is set out in the methodology.