MP3 to FLAC Converter
Decodes your MP3 and re-encodes it with the FLAC encoder, so nothing more is lost from here on. What MP3 compression already threw away cannot be brought back, and the FLAC will be much larger than the file you started with.
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What MP3 to FLAC Actually Does
MP3 is a lossy format: when the file was first encoded, parts of the signal were analyzed, judged inaudible and deleted. FLAC is the opposite kind of codec. It compresses audio the way ZIP compresses a document, so the decoded output is bit-for-bit what went in. Converting between them is therefore a one-way street in only one sense: you get a container that will never degrade again, not a recovery of the original recording.
On this page the job is a single ffmpeg pass. Your MP3 is decoded to PCM and handed straight to the FLAC encoder at its default compression level, with no filters in between. Nothing is normalized, denoised or resampled, and there is no quality, bit-depth or compression-level selector, so every file is treated identically. The output keeps your file name with a .flac extension.
Preserved: the sample rate of the MP3 is kept as it is, so a normal 44.1 kHz track stays 44.1 kHz; channel layouts up to eight channels are kept; and title, artist and album tags carry across into the FLAC. Not preserved: embedded cover art is dropped, as it is on every conversion we run, and chapter markers in long MP3s such as audiobook rips are not carried into FLAC, which has no real chapter model. Files with more than eight channels fail outright, because the FLAC encoder refuses them.
The people who ask for this conversion usually have a practical reason rather than an audio one: a library or tagging workflow that only indexes FLAC, a hardware player or DJ program that wants FLAC, a mastering or editing chain where every intermediate step must be lossless, or a collection being standardized on one format before archiving. All of those are fine reasons. Hoping the music will sound better is not; it will sound exactly the same.
How to Convert MP3 to FLAC
- Check the MP3 plays properly from start to finish first. A partially downloaded or truncated MP3 will fail here with an invalid data error rather than convert part way.
- If tags matter to you, fix them in the MP3 before converting. Title, artist and album are carried over, so it is less work than retagging the FLAC afterwards.
- Drag your MP3 files onto the upload box or click to browse. Guests get 50 MB per file and 10 files per request; a free account raises that to 100 MB per file, Plus to 200 MB and 25 files, Pro to 1 GB and 50 files.
- Press Convert. Each track is decoded and re-encoded on our servers as its own job, so a mixed batch of short and long tracks is fine. Typical album-length tracks come back within a couple of seconds of the upload finishing.
- Download the FLAC files one by one from the results list, and expect them to be much bigger than the MP3s. Links last about four hours, so grab them in the same session.
- Keep the MP3s until you have checked the FLACs in your player. The conversion adds no quality, so the originals are still perfectly usable.
Details Worth Knowing
- One ffmpeg decode plus a FLAC encode at the encoder's default level: lossless with respect to the decoded MP3 audio, so no further generation loss
- No resampling and no channel folding: 44.1 kHz stays 44.1 kHz, mono stays mono, and multichannel layouts up to eight channels are kept
- Title, artist and album tags are carried from the MP3 into the FLAC so your library stays searchable
- Accepts any MP3 bitrate, including VBR files and low-bitrate speech recordings, with no settings to pick
- One FLAC per input file, named after the original, converted on our servers rather than in your browser
- Also accepts the other audio sources this converter supports, so you can send AAC or M4A tracks in the same batch when you are standardizing a mixed folder
Video Tutorial
Watch this step-by-step tutorial to learn how to convert MP3 files to FLAC format online for free using MiConvert.com. No software installation required.
Frequently Asked Questions
During conversion from MP3 to FLAC, is music data lost?
No data is lost in this step. The MP3 is decoded and the FLAC encoder stores that decoded audio exactly, so the FLAC will decode back to the same samples. The loss happened earlier, when the MP3 was first encoded, and that is permanent. Two things do get dropped in this step, though: embedded cover art and any chapter markers.
Can I get a 16-bit, 44.1 kHz FLAC?
There is no bit-depth or sample-rate control on the page, so you cannot request a specific target. We do not resample, which means an ordinary 44.1 kHz MP3 produces a 44.1 kHz FLAC. If your workflow needs an exact, enforced bit depth and rate, run ffmpeg or a desktop editor locally where you can set those flags yourself.
What about 24-bit FLAC from MP3?
That is not something a converter can meaningfully provide. MP3 carries no 24-bit information, so padding the samples out to 24 bits would only make the file bigger with no extra detail, and we do not offer that option in any case.
Why is the FLAC so much larger than the MP3?
Because FLAC stores every sample of the decoded audio rather than a compressed approximation of it. The exact size depends on the music, but expect a substantial increase. If storage is the priority, keeping the MP3 is the rational choice.
Does album art transfer?
No. Picture streams are removed on every conversion here, so the FLAC arrives without artwork even though the MP3 had it. Re-add it afterwards with a tag editor such as Mp3tag, Kid3 or Picard if your player shows covers.
Can I convert a whole folder or an album in one go?
You can select multiple files in one request, up to 10 for guests and free accounts, 25 on Plus and 50 on Pro, but folders are not uploaded as folders and there is no combined ZIP download, so each track is downloaded individually. Guest and free use is also capped at 10 conversion jobs per hour per IP address.
Some of my MP3s fail. Why?
The usual cause is a damaged or incomplete file, which shows as an invalid data error; re-download or re-rip it. A message about DRM-protected or undecodable data means ffmpeg could not read most of the stream, so you need an unprotected, undamaged copy. Very long files hit a 30-minute processing cap, and files with more than eight audio channels are refused by the FLAC encoder.
What happens to my files on your servers?
The conversion runs on our servers, never in your browser. Your uploaded MP3 is deleted as soon as the job ends, and the FLAC with its download link is deleted automatically after roughly four hours. File names, sizes and outcomes are logged, and if you are signed in a history entry is kept on your account. Anyone with the download link can use it until it expires, so do not share it.