A FLAC file is an audio file that stores music in full quality while taking less space than a WAV. The name stands for Free Lossless Audio Codec. Lossless means that when you play the file back, you get exactly the same sound that went in. If you have songs in FLAC, you can upload them straight to the stem splitter, because FLAC is one of the formats we accept.
What Is a FLAC File? Lossless Audio Format Explained Simply
October 27, 2026
FLAC is a lossless audio format that shrinks a file without losing any sound. Learn how it differs from MP3 and WAV, how big the files are, and how to use FLAC.
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What does FLAC stand for?
FLAC stands for Free Lossless Audio Codec. "Free" means the format is open: anyone can use it without a license fee. "Lossless" means no sound is thrown away. "Codec" is a short word for a method of shrinking and expanding data.
How does FLAC work?
Think of a zip file. A zip file makes a document smaller, and when you unzip it, the document is exactly as it was. FLAC does the same for audio. It finds patterns in the sound data, stores them in a shorter form, and rebuilds the original when you play it.
That is why FLAC is called lossless compression. The file is smaller than the raw audio, but nothing is missing.
This is different from lossy compression, which MP3 and AAC use. Lossy formats remove parts of the sound that the format guesses you will not notice. The file gets much smaller, but the removed detail is gone for good.
FLAC vs WAV vs MP3
| FLAC | WAV | MP3 | |
|---|---|---|---|
| Type | Lossless, compressed | Usually uncompressed | Lossy, compressed |
| Sound quality | Same as the source | Same as the source | Very close at high bitrates, not identical |
| File size | Smaller than WAV | Largest | Smallest |
| Tags and cover art | Yes | Limited | Yes |
| Plays everywhere | Most modern players | Almost everything | Almost everything |
The WAV file and FLAC hold the same audio. FLAC just packs it into a smaller file. The exact saving depends on the music: a quiet acoustic track shrinks more than a loud, dense one.
Why do people use FLAC?
- Music collections. Keep your CDs at full quality without filling your drive.
- Audiophile listening. Good speakers and headphones can reveal differences a phone speaker cannot.
- Archiving. Store a master copy that never loses anything, no matter how many times you copy it.
- Downloads from music stores. Some stores sell music as FLAC.
- Tagging. FLAC supports tags for artist, album and track number, and can carry cover art.
Can you hear the difference?
It depends. Between FLAC and the original, there is none, because the audio is identical. Between FLAC and a high-quality MP3, many people cannot tell on ordinary earbuds in a noisy place. On good gear in a quiet room, some can. The biggest gap shows when you go further than listening: if you plan to edit, remix or process a track, starting from lossless means you are not stacking one loss on top of another.
Does converting MP3 to FLAC improve quality?
No. Once an MP3 has thrown away detail, turning it into a FLAC does not bring that detail back. You get a larger file with the same sound. A FLAC is only truly lossless if it was made from a lossless source, such as a CD rip or a studio WAV.
If an old MP3 sounds dull and you want some of the highs back, that is a different job. The Audio Upscaler restores missing high frequencies in a recording, though it cannot turn a very poor recording into a studio one.
How to open and play a FLAC file
Most current phones, computers and media players play FLAC. If one does not, a free media player that supports it will. Some older devices and some streaming and editing tools do not, which is the main reason people still convert to MP3 or WAV.
Using FLAC with Unmix Studio
Unmix Studio accepts FLAC along with MP3, WAV and M4A. A song can be up to 10 minutes long. Starting from a lossless file gives the AI the cleanest sound to work from.
To split a FLAC into stems:
- Open the stem splitter and sign in with Google. New accounts get 5 free credits.
- Upload your FLAC file.
- Press the big orange button. The price in credits shows on the button before you start.
- Wait a minute or two. In our own test, a 4 minute 44 second song split into 6 stems in 56 seconds and cost 5 credits.
- Download the stems you want as MP3 files at 320 kbps.
The downloads are MP3, not FLAC. Each stem from that 4 minute 44 second song was about 10.9 MB. Mixed songs can leave a little bleed between stems, especially live recordings and tracks with a lot of reverb.
If you need lossless stems for a final master, keep your original FLAC or WAV safe and use the MP3 stems for the work in progress.
FAQ
What is a FLAC file?
A FLAC file is a lossless audio file. It holds the same sound as the original recording but is smaller than an uncompressed WAV.
Is FLAC better than MP3?
For quality, yes, because FLAC loses nothing and MP3 does. The trade-off is size: FLAC files are much bigger than MP3 files. For everyday listening on a phone, many people choose MP3.
Is FLAC the same as WAV?
They sound the same, but FLAC is compressed and WAV usually is not, so a FLAC is smaller. You can convert between them without losing any quality.
Can I upload a FLAC file to Unmix Studio?
Yes. FLAC works for the stem splitter and the single-purpose pages, up to 10 minutes per song. Most tools cost 1 credit per minute of song, and new accounts get 5 free credits.
Will my stems come back as FLAC?
No. Downloads are MP3 at 320 kbps. Keep your original FLAC if you want a lossless copy of the full song.