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FLAC to MP3 converter

Convert lossless FLAC audio to MP3 with adjustable bitrate.

Free & unlimited
All processing happens in your browser — files never leave your device. The audio engine loads once from a CDN.

FLAC stores audio losslessly at roughly half the size of WAV, which makes it the standard for ripping and archiving CDs — and a poor fit for a phone, where a single album can run to 300 MB. This converter encodes FLAC to MP3 with libmp3lame in your browser. Because FLAC is lossless, this is a first-generation encode: unlike converting one lossy format to another, the encoder is working from the full original signal, so 320 kbps or VBR genuinely gets you close to transparent. Bitrate runs from 128 to 320 kbps, there is a VBR option, and you can force a sample rate if the FLAC is a high-resolution 96 kHz file that a target device will not accept. Vorbis comment tags are carried across.

Key facts about FLAC to MP3 converter

Key facts about FLAC to MP3 converter
Source is losslessFLAC holds the complete original signal, so this is a first-generation lossy encode — the best case for MP3 quality
Bitrates128, 192, 256 and 320 kbps, defaulting to 320 because the source deserves it
VBR optionlibmp3lame quality level 2, averaging around 190 kbps and spending bits where the music needs them
Typical size dropA 30 MB FLAC track becomes roughly 7 MB at 320 kbps or 4.5 MB at 192 kbps — a five to seven times reduction
Sample rateMatched to the source by default, or forced to a standard rate for devices that reject 88.2 or 96 kHz
High-resolution caveatMP3 tops out at 48 kHz, so a 96 kHz FLAC is resampled during conversion whether or not you ask for it
Bit depthA 24-bit FLAC is reduced to the MP3 encoder's internal representation; MP3 has no concept of bit depth
MetadataVorbis comments are carried into ID3 tags by default
BatchConvert a whole album at once and download the set as a ZIP
Size cap200 MB per file, which covers a very long FLAC track or a full-disc rip

What happens to your file

The encode runs on ffmpeg compiled to WebAssembly in a Web Worker inside this tab. Your FLAC files are written into that worker's in-memory filesystem, encoded to MP3, and read back as blobs; the batch ZIP is assembled in the browser too. Nothing is uploaded and no copy is stored anywhere. The one network request is the first-time download of the ffmpeg core — about 32 MB of fixed public code from the jsDelivr CDN, cached by your browser and shared across every audio tool here. It carries no part of your music.

About this tool

  1. 1

    Add your FLAC files

    Drop one file or a whole album folder. Each file can be up to 200 MB, which is comfortably more than any single CD track.

  2. 2

    Choose the bitrate

    320 kbps is the default and the right call from a lossless source. 192 kbps halves the size again and is still good; 128 kbps is for speech, not music.

  3. 3

    Consider VBR

    Variable bitrate produces a slightly smaller file at similar quality by spending bits only where the music is complex. Leave it off for very old hardware players.

  4. 4

    Check the sample rate

    Leave it on auto for a standard 44.1 kHz CD rip. If the FLAC is 88.2 or 96 kHz high-resolution audio, it is resampled regardless, since MP3 cannot exceed 48 kHz.

  5. 5

    Convert

    Files run one after another with per-file progress and an estimated output size shown before you start.

  6. 6

    Download

    Individually or as a ZIP. Keep your FLAC originals — they are the master, and the MP3s are the listening copies.

Specs & compatibility
InputFLAC (.flac, audio/flac), up to 200 MB per file
OutputMP3 via libmp3lame, constant or variable bitrate
Bitrates128, 192, 256, 320 kbps
Sample rateAuto (match source) or forced; MP3's maximum is 48 kHz
MetadataVorbis comments mapped to ID3 tags when preservation is on
Batch outputIndividual downloads or one client-side ZIP
EngineSingle-threaded ffmpeg.wasm 0.12.10, ~32 MB core cached after first use
BrowsersChrome, Edge, Firefox and Safari 15+
  • Keep the FLAC files. Once you have converted to MP3 there is no way back to lossless, and the FLAC is what you re-encode from next time a format changes.
  • 320 kbps constant bitrate is the format's ceiling and what most people choose from a lossless source. VBR is slightly smaller for similar quality.
  • A 96 kHz high-resolution FLAC has to be resampled to 48 kHz or below because MP3 has no higher rate. That is a real change, not a formality.
  • For a phone, 192 kbps is usually the smart trade — roughly seven times smaller than the FLAC and indistinguishable through earbuds on a train.
  • Leave metadata preservation on. FLAC albums are usually well tagged, and retagging a fifteen-track MP3 album by hand is a waste of an evening.
  • If you want lossless on a device that will not read FLAC, convert to ALAC or WAV with the general audio converter instead of dropping to MP3.
  • Batch ZIPs are built in your browser, so a sixty-track box set is bounded by your device's memory rather than a server limit.
  • Bitrates from 128 to 320 kbps, defaulting to 320
  • Optional MP3 variable bitrate
  • Sample rate matched to source or forced
  • Vorbis comment tags carried into ID3
  • Estimated output size before you convert
  • Batch conversion with per-file progress
  • ZIP download for whole albums
  • Making a phone-sized copy of a lossless CD rip collection
  • Converting a Bandcamp FLAC purchase for a car stereo that only reads MP3
  • Preparing MP3 versions of mastered tracks for a submission that requires them
  • Shrinking an archived FLAC library for a portable player with limited storage
  • Producing MP3 listening copies while keeping FLAC masters on a NAS
  • Converting a high-resolution FLAC download into something an older DAP will actually play
Roughly five to seven times smaller, depending on the bitrate you choose and how compressible the music was. A typical 30 MB FLAC album track comes out around 7 MB at 320 kbps, 5.5 MB at 256, and 4.5 MB at 192. FLAC itself is already compressed — usually to about half the size of the equivalent WAV — so the saving here comes entirely from discarding audio information that the psychoacoustic model judges inaudible, which is exactly what lossless compression refuses to do.
At 320 kbps from a lossless source, rarely, and never through the conditions most listening actually happens in. This is the good case for MP3: the encoder is working from the complete original signal rather than from an already-degraded copy, so it can make its own decisions cleanly. Where you might hear it is on cymbals, applause and other dense high-frequency material, on good headphones, in a quiet room. At 192 kbps the margin narrows further but still holds for casual listening.
You can create a FLAC file from an MP3, but it will not restore anything. Lossy encoding throws information away permanently, and wrapping the result in a lossless container simply preserves the damaged version at a much larger size. This is why the real advice is to keep your FLAC originals: they are the master copy, and every future conversion — to a new codec, a different bitrate, a different device — should start from them rather than from an MP3.
Both are reduced, because MP3 cannot represent either. The format has no concept of bit depth, so a 24-bit source is simply encoded through the normal MP3 path. Sample rate is a harder limit: MP3 supports up to 48 kHz, so an 88.2 or 96 kHz high-resolution FLAC is resampled down during conversion whether or not you set the sample rate control. If the high-resolution properties matter to you, keep the FLAC and use a player that supports it.
Yes, when metadata preservation is left on, which it is by default. FLAC stores metadata as Vorbis comments and MP3 uses ID3 tags; the conversion maps the standard fields across, so artist, album, title and track number survive. That is worth checking on a large batch before you delete anything, because an untagged album is significantly more annoying to fix afterwards than it is to verify now. Embedded artwork generally carries through as well.
No. The encode happens in ffmpeg compiled to WebAssembly, running in a Web Worker on your own device. Your FLAC files are written into that worker's in-memory filesystem and the MP3s come back as blobs in your tab; the batch ZIP is built in the browser too. The only network request is the one-time fetch of the ffmpeg core — about 32 MB of fixed public code from the jsDelivr CDN, cached afterwards and shared with every other audio tool here.

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