MP3 to FLAC Converter
Converting MP3 to FLAC freezes the decoded MP3 in a lossless file: nothing more is lost from here on, and nothing already lost comes back. That is useful in a few specific situations, and this page explains which ones.
Audio Converter
or drop MP3, WAV, M4A … files here ·
Max 95 MB per file· Up to 20 files· Deleted after 30 minutes
Files are processed on our servers and deleted after 30 minutes.
Constant bitrate (CBR) gives a predictable size and works on every player. Variable bitrate (VBR) spends bits where the music needs them and is usually smaller at the same quality.
Keep the source rate unless a device asks for one. 44.1 kHz is CD standard, 48 kHz is video standard, 8 kHz is used by phone systems and AMR.
Mono halves the size of lossless files and is fine for voice recordings.
16-bit is CD quality. 24-bit keeps headroom for editing and mastering; converting a 16-bit source up does not add detail.
Optional. Seconds (e.g. 75) or minutes:seconds (1:15). Leave empty to start at the beginning.
Optional. Same format as the start time. Leave empty to keep everything up to the end.
How to use this tool
- 1
Add your MP3 files
Upload up to 20 MP3s, each up to 95 MB. Albums with embedded artwork are fine.
- 2
Leave the defaults for most files
Bit depth starts at 16-bit, which already holds everything an MP3 decoder outputs. Keep Sample rate on Same as source and Keep tags and cover art switched on.
- 3
Press Convert to FLAC
Each MP3 is decoded once and compressed losslessly. Download the FLAC files individually or as a ZIP; uploads are deleted after 30 minutes.
Good reasons to convert MP3 to FLAC
The strongest reason is editing. Every time you open an MP3, change it and save as MP3 again, the encoder makes fresh decisions about what to throw away, and artifacts stack up. Decode once, keep the working copy in FLAC, and the damage stops at the first generation. The same logic applies to a podcast intro or a ringtone source you expect to revise.
The second is uniformity. Some people run a music server, a car head unit or a DJ library that is configured around FLAC, and a handful of MP3-only tracks are the odd ones out. Converting them keeps playlists, scanning rules and tag editors consistent. If your source is a recording you made yourself, start from the original instead: WAV to FLAC keeps the full quality that the MP3 never had.
MP3 to FLAC quality: three common beliefs
MythFLAC restores the detail the MP3 removed.
FactDecoding gives back only what the MP3 kept. The FLAC stores those samples perfectly, gaps included.
MythAny FLAC file is studio quality.
FactFLAC is lossless relative to its input. A FLAC made from a 128 kbps MP3 has the same cut-off highs as the MP3.
MythGoing MP3 to FLAC and back to MP3 is harmless.
FactThe second MP3 encode is another lossy generation. Keep the original MP3 for listening copies instead of re-encoding.
MP3 to FLAC converter: what happens to file size
- per minute, MP3 at 128 kbps
- ≈ 1 MB
- per minute, MP3 at 320 kbps
- ≈ 2.4 MB
- per minute, FLAC from either one
- ≈ 5–7 MB
- per minute, the same audio as WAV
- ≈ 10.6 MB
FLAC size depends on the decoded audio, not on the MP3 bitrate, so a 128 kbps file and a 320 kbps file of the same song produce FLACs of similar size. Plan for the library to grow three to six times. That is the clearest sign that the conversion adds storage, not sound.
If you only need decoded audio for a single job, MP3 to WAV gives the same samples without tags. For the full list of output formats and what each option does, see the audio converter.
MP3 and FLAC: specifications
MP3
MP3 audio
MP3 (MPEG-1 Audio Layer III) is a lossy audio format developed largely at the Fraunhofer Institute and standardised by MPEG in 1993. It removes sounds the ear is unlikely to notice, shrinking music to about a tenth of CD size at 128–320 kbps. All patents have expired, and every phone, car stereo, browser and media player supports it. Quality loss is audible at low bitrates and accumulates with re-encoding.
- Compression
- Lossy
- Transparency
- –
- Animation
- –
- Introduced
- 1993 · Fraunhofer IIS / MPEG
FLAC
Free Lossless Audio Codec
FLAC is an open-source lossless audio codec released by Josh Coalson in 2001 and now maintained by the Xiph.Org Foundation. It reduces audio to about 50–70% of the original size without losing any quality, so a FLAC file can be decoded back to an exact copy of the source. It supports high resolutions and rich metadata and is popular for CD rips and hi-res music downloads. Files are much larger than MP3, and some Apple apps and older devices have limited support.
- Compression
- Lossless
- Transparency
- –
- Animation
- –
- Introduced
- 2001 · Xiph.Org Foundation (Josh Coalson)
People convert MP3 to FLAC to give a mixed library one lossless format or to stop compression loss piling up on files they will keep editing; the FLAC preserves the decoded MP3 exactly but cannot add back what the MP3 encoder removed.
Questions about MP3 to FLAC
Why convert MP3 to FLAC if the quality stays the same?
Mostly for consistency and for editing. A player, media server or DJ library set up around FLAC handles one format more predictably, and an edited MP3 saved as FLAC stops picking up a new layer of compression error each time it is exported.
Can a store or label tell that my FLAC came from an MP3?
Usually, yes. A spectrogram in Audacity or Spek shows a sharp ceiling where the MP3 encoder's low-pass filter cut the highs, often near 16 kHz for 128 kbps files. Platforms such as Bandcamp ask for true lossless masters, so upload the original WAV or FLAC from your session instead.
Will the FLAC be larger than the MP3?
Yes, several times larger. FLAC has to store every decoded sample exactly, including the noise-like detail an MP3 encoder adds, so a 1 MB-per-minute MP3 becomes a FLAC of roughly 5 to 7 MB per minute.
Should I pick 24-bit for an MP3 source?
There is no benefit. MP3 has no native bit depth, and 16-bit is already finer than the quantization noise the encoder left behind, so padding to 24-bit only grows the file. Choose 24-bit only if you will process the audio heavily afterwards.
Do ID3 tags and album art carry over into FLAC?
With Keep tags and cover art on, title, artist, album and track number move from ID3 frames into FLAC's Vorbis comments, and the embedded cover goes into a FLAC picture block. Uncommon ID3 frames such as lyrics or chapter marks may not have a direct equivalent.