Convert FLAC to MP3 Online Free
Convert your .flac files to .mp3 format. Free, fast, and processed entirely in your browser — your files never leave your device.
Convert FLAC to MP3 for phones, cars, and Bluetooth — without ruining the sound
FLAC-to-MP3 is the conversion audiophiles do reluctantly: you have a beautiful lossless library, but the car stereo can't play it, the phone storage can't hold it, and Bluetooth re-encodes it anyway. The good news is that with the right bitrate, the MP3 will be sonically indistinguishable from the FLAC on the gear most people listen on. Here's how to pick that bitrate and three tools to do the conversion cleanly.
When converting FLAC to MP3 makes sense
- You're loading music onto a phone, iPad, or storage-limited DAP. A 1 TB FLAC library compresses to ~150 GB at 320 kbps MP3 with no audible loss on consumer gear.
- You're putting tracks on a USB drive for an older car head unit. Many car stereos still don't read FLAC; MP3 is universal.
- You're listening over Bluetooth (AirPods, Sony WH-1000XM, Bose, Sonos). Bluetooth re-encodes audio in flight using SBC, AAC, or LDAC — the FLAC vs MP3 difference disappears the moment it leaves your phone, so why pay 5× the storage cost?
- You're sharing music with friends. MP3 is the universal lossy format; FLAC will stump some recipients (Apple Music ecosystem, certain Android players).
- You're putting a track on a website or social platform. They'll re-encode anyway, so save the upload bandwidth.
When you should NOT convert FLAC to MP3
- It's your master archive. Keep the FLACs. Hard drives are cheap; re-ripping CDs is not.
- You're listening on high-end gear in a treated room. Trained listeners on flat-response monitors can tell 256 kbps MP3 from FLAC. 320 closes most of the gap, but not all of it.
- You're going to keep editing the file in a DAW. MP3 is lossy; multi-generational lossy edits stack up. Edit FLAC, then export MP3 once at the end.
- Your delivery target requires lossless (mastering, broadcast, sample library). Send FLAC or WAV, not MP3.
How small the MP3 will be
FLAC is already a compressed (lossless) format, so it's smaller than WAV but bigger than MP3. Converting to MP3 saves 60-80% versus the FLAC, depending on the bitrate you pick.
| Duration | FLAC | MP3 | Note |
|---|---|---|---|
| 1 minute | ~5-6 MB (FLAC) | ~2.4 MB at 320 kbps | 40-48% — transparent to most ears |
| 1 minute | ~5-6 MB (FLAC) | ~1.4 MB at 192 kbps | 23-28% — fine for casual listening / Bluetooth |
| 1 hour | ~300-360 MB (FLAC) | ~144 MB (320 kbps) / ~86 MB (192 kbps) | 60-75% reduction |
| 1000-track library | ~150-180 GB (FLAC) | ~50-70 GB at 320 kbps | Fits on a phone instead of a NAS |
Source: 16-bit / 44.1 kHz stereo FLAC at the typical compression level. CBR sizes shown — VBR can be 5-15% smaller for similar perceived quality.
Where MP3 plays (basically everywhere)
Works with
- Every smartphone (iOS, Android), tablet, computer, smart speaker
- Every car head unit, including pre-Bluetooth USB-only ones
- Every Bluetooth speaker and headphone
- iTunes / Apple Music (FLAC does NOT work here, MP3 does)
- Spotify / SoundCloud / YouTube uploads (they accept FLAC but re-encode it; just upload MP3 if convenient)
- Email, chat, social media — well under attachment limits
Does not work with
- High-end mastering and broadcast workflows — they need WAV/AIFF/FLAC
- Sample-accurate editing — MP3 frame boundaries (1152 samples) get in the way
- Premium audiophile listening — golden ears on high-end systems can spot 320 kbps in some material
How to convert FLAC to MP3
Convert with WaveSieve (browser, free, no upload)
Quickest path. Conversion runs in your browser via FFmpeg.wasm — your file never leaves your device, and no account is needed. Default output is 192 kbps which is plenty for phone/Bluetooth listening.
- Drop your FLAC file onto the upload area at the top of this page. Up to 100 MB per file.
- In the converter, output is set to MP3 by default. Leave it.
- Click "Convert to MP3" — encoding takes 5-30 seconds depending on file length.
- Click "Download" to save the MP3.
Convert with foobar2000 (Windows, free, audiophile-grade)
foobar2000 is the audiophile go-to for FLAC library management on Windows. It uses LAME for MP3 encoding and preserves all metadata including album art.
- Download foobar2000 (free at foobar2000.org). On first launch, it will prompt to install the LAME encoder; let it.
- Add your FLAC files: File → Open, or drag them into the playlist.
- Right-click the tracks → Convert → ... → New: 'MP3 (LAME)'.
- In the encoder settings, choose preset: V0 (best VBR) or 320 CBR for archival. Click OK.
- Pick a destination folder. foobar2000 will keep all metadata and album art.
Convert with FFmpeg (command line, batch, cross-platform)
Best for scripted batch jobs across Windows/Mac/Linux. Uses the same LAME encoder as Audacity and foobar2000.
- Install FFmpeg: brew install ffmpeg (macOS), winget install ffmpeg (Windows), or sudo apt install ffmpeg (Linux).
- Open a terminal in the folder with your FLACs.
- Single file at V0 VBR (recommended): ffmpeg -i input.flac -c:a libmp3lame -q:a 0 -map_metadata 0 output.mp3
- 320 kbps CBR: ffmpeg -i input.flac -c:a libmp3lame -b:a 320k -map_metadata 0 output.mp3
- Whole folder, V0 with metadata: for f in *.flac; do ffmpeg -i "$f" -c:a libmp3lame -q:a 0 -map_metadata 0 "${f%.flac}.mp3"; done
Things that surprise people
V0 VBR is better than 320 CBR for almost every use case
320 kbps CBR allocates the same bitrate to every passage — 320 kbps to a moment of silence and 320 kbps to a dense full-band climax. V0 (VBR -q:a 0) adapts: roughly 240 kbps average, but bursts up to 320 on demanding parts. The result is the same perceived quality with a smaller file. Audiophiles default to V0 for MP3 of FLAC.
Below 256 kbps starts to hurt
192 kbps is fine for Bluetooth listening and phone-on-the-go scenarios. But for high-end Bluetooth (LDAC, aptX HD) or wired listening on quality gear, drop to 192 only if you're space-constrained. 256-320 kbps closes the audible gap to FLAC for almost everyone.
Don't lose your metadata in the conversion
FLAC carries detailed Vorbis comments (artist, album, track, year, embedded album art). MP3 uses ID3 tags — different format, but the data maps over fine. Make sure your tool preserves it: foobar2000 and Mp3tag handle this perfectly; FFmpeg needs -map_metadata 0; WaveSieve currently does not write metadata into the output.
Frequently Asked Questions
What's the smallest MP3 bitrate I can use without obviously hurting music?
192 kbps VBR (V2) is the practical floor for music — below that you start to hear high-frequency smearing on cymbals and bright vocals. 192 VBR averages ~190 kbps and produces files 60-65% the size of 320 CBR with very subtle quality differences.
Should I keep the original FLACs after converting?
Yes, always — assuming storage allows. The MP3 is a derivative; if you ever want to convert again (to Opus, AAC, or a different MP3 bitrate), you should start from the FLAC, not the already-degraded MP3. Treat the FLAC as your master.
My FLAC is 24-bit / 96 kHz. Does that change the MP3 process?
Slightly. MP3 only supports 32 / 44.1 / 48 kHz sample rates and uses 16-bit equivalent dynamic range. Your encoder will downsample to 44.1 or 48 kHz and convert bit depth automatically. The audible loss from this step is real but very small. If you need lossless 24/96 portability, use Opus or AAC at high bitrate instead.
Will the album art transfer?
If your tool preserves metadata: yes. foobar2000 and Mp3tag carry the embedded image cleanly. FFmpeg needs -map_metadata 0 (and album art often comes through, but for guaranteed transfer use -c:v copy as well). WaveSieve currently does not preserve embedded album art — use foobar2000 or FFmpeg if metadata matters.