What happens when you convert MP3 to FLAC
- The audio is decoded and written as FLAC at compression level 5.
- FLAC is lossless, but it cannot restore what the MP3 encoder already discarded. The FLAC will sound identical to the MP3 and be several times larger.
How to convert MP3 to FLAC online
- Press "Choose MP3 files" and select one or more files, or drag them onto the box. You can add files of any size your device can hold in memory.
- Adjust the settings if you need to: the bitrate controls quality and size. The defaults suit most people.
- Press "Convert to FLAC". The first audio or video conversion downloads the converter engine, about 32 MB, which your browser then keeps for next time.
- Save each FLAC with its download button. Close the tab and every trace of the files is gone from memory.
Why convert MP3 to FLAC?
MP3 files usually come from music libraries, podcasts and anything that has to play everywhere. People convert them to FLAC because FLAC keeps every detail of the original while cutting the size roughly in half compared with WAV.
In short, MP3 is good at what it was made for, and FLAC is the more practical choice when the file has to play on another device or app. MP3 plays in every browser, phone, car stereo and media player, while FLAC plays in current browsers and most Android devices; iPhones play it in the Files app.
How to convert MP3 to FLAC on Windows, Mac, iPhone and Android
On Windows
Open this page in Chrome, Edge or Firefox, drag your MP3 files in from File Explorer, and press Convert. Each FLAC is saved to your Downloads folder. If you prefer a desktop program, VLC can also convert MP3 to FLAC: choose Media, then Convert / Save.
On a Mac
Safari, Chrome and Firefox all work. Drag the MP3 files from Finder onto the drop zone and the FLAC files land in Downloads.
On iPhone and iPad
Open the page in Safari and tap Choose MP3 files. You can pick from Photos or from the Files app. The converted FLAC appears in Files, in the Downloads folder.
On Android
Open the page in Chrome, tap Choose MP3 files and pick them from Files or your gallery. The FLAC is saved to the Download folder, where any file manager can find it. Keep the screen on while a long video converts, because Android may pause a tab in the background.
Best settings for MP3 to FLAC
FLAC is lossless, so there is no quality setting: every sample of the decoded MP3 is kept. What changes is size. CD-quality stereo, 44.1 kHz at 16 bits, takes about 10 MB per minute as uncompressed PCM, and roughly half to two thirds of that once compressed losslessly.
Since the MP3 was lossy, the FLAC will sound identical to it, not better. Convert to FLAC when a program requires it, not to improve quality.
MP3 vs FLAC: the differences
| MP3 | FLAC | |
|---|---|---|
| Full name | MPEG-1 Audio Layer III | Free Lossless Audio Codec |
| Type | audio | audio |
| Created by | the Fraunhofer Institute | Josh Coalson and the Xiph.Org Foundation |
| First released | 1993 | 2001 |
| Compression | Lossy | Lossless |
| Usually contains | MP3 audio, typically 128 to 320 kbps | FLAC lossless audio, up to 32-bit and 655 kHz |
| In a browser | plays in every browser, phone, car stereo and media player | plays in current browsers and most Android devices; iPhones play it in the Files app |
| Common uses | music libraries, podcasts and anything that has to play everywhere | CD rips, hi-res music stores and audio archives |
| MIME type | audio/mpeg | audio/flac |
About MP3 and FLAC files
What is an MP3 file?
MP3 is the most widely supported audio format there is, which is its whole appeal. At 320 kbps most listeners cannot tell it from the original; at 128 kbps cymbals and applause start to smear.
What is a FLAC file?
FLAC shrinks audio to about half to two thirds of WAV size without losing a single sample, so it can be decoded back to a bit-identical copy of the original.
MP3 to FLAC not working? Common problems
- The conversion is slow. Audio and container changes take seconds, but re-encoding video runs on your own processor. Lower the resolution to 720p, close other tabs, and keep the device plugged in.
- The tab stops or reloads on a very large file. Browsers limit how much memory one tab can use, around 2 GB and less on phones. Split long recordings or convert them on a computer.
- Song titles are missing. Tags such as title and artist are copied when FLAC can store them, but cover art is not carried over.
Convert MP3 to FLAC with ffmpeg
This converter runs ffmpeg inside your browser. If you would rather use the ffmpeg command line on your own computer, this command produces an equivalent FLAC with the same kind of settings:
ffmpeg -i input.mp3 -vn -c:a flac output.flacReplace input.mp3 with the name of your file. For a whole folder of MP3 files, run the command in a loop, or drop them all on the converter above, which processes them one after another.
MP3 to FLAC converter FAQ
Will I lose quality converting MP3 to FLAC?
No further quality is lost, because FLAC is written losslessly. Detail the MP3 compression already removed does not come back.
Why is the FLAC a different size from the MP3?
The FLAC is usually larger, because it stores every sample without compression losses, while the MP3 was compressed lossily.
Are my MP3 files uploaded anywhere?
No. The conversion runs inside this browser tab using ffmpeg compiled to WebAssembly, so your files stay on your device. You can disconnect from the internet after the page and converter engine have loaded and it still works.
Can I convert several MP3 files to FLAC at once?
Yes. Select or drop as many files as you like; they are converted one after another and each gets its own download button.
How do I open a FLAC file?
FLAC plays in current browsers and most Android devices; iPhones play it in the Files app. FLAC is common for CD rips, hi-res music stores and audio archives.
Is this MP3 to FLAC converter free?
Yes. There is no sign-up, no watermark and no limit on how many files you convert. The site is paid for by advertising, and because conversions run on your device there is no server cost per file.
Can I convert MP3 to FLAC on my phone?
Yes. The converter works in Safari on iPhone and iPad and in Chrome on Android. Converted files are saved to the Downloads folder.