Online FLAC Compressor
Optimize FLAC files with lossless compression
FLAC (Free Lossless Audio Codec) preserves every bit of your original recording, but the files can be enormous — a single album often exceeds 500 MB. Our free FLAC compressor lets you squeeze those files down by choosing a higher compression level (0 through 8) without sacrificing a single sample of audio data. You can also trim bit depth from 24-bit to 16-bit or downsample the rate for further savings, though those steps are lossy. All processing happens in your browser, so your music never leaves your device.
Features
- Lossless compression levels 0-8 — smaller file with bit-perfect audio
- Reduce file size by 10-30% compared to level-0 encoding
- Optional bit depth conversion: 24-bit to 16-bit (CD quality)
- Downsample rate: 96 kHz → 48 kHz → 44.1 kHz
- Stereo-to-mono conversion for additional space savings
- Browser-based processing — no files uploaded to any server
How to Compress a FLAC File
- Upload your FLAC file by dragging it into the drop zone or clicking to browse
- Choose a compression level: Fast (0) for speed, Default (5) for balance, Best (8) for smallest size
- Optionally adjust bit depth, sample rate, or channel count under Advanced settings
- Click "Compress" and download the optimized FLAC file
Frequently Asked Questions
Does FLAC compression lose quality?
No. FLAC is a lossless codec, meaning every compression level (0-8) produces bit-for-bit identical audio when decoded. The level only controls how much CPU time the encoder spends looking for patterns. Higher levels find more patterns, yielding a smaller file, but the audio is always perfect.
What compression level should I use?
Level 5 (Default) is the best general choice — it offers a strong size reduction without noticeably slow encoding. Level 8 (Best) squeezes out an extra 1-3% but can take significantly longer, especially for long recordings. Level 0 (Fast) is ideal when encoding speed matters more than file size.
How much smaller will my FLAC file be?
Typical FLAC files compress to 50-70% of the original WAV size. Switching from level 0 to level 8 can save an additional 5-10% on top of that. The actual ratio depends on the audio content — simple recordings (speech, solo instruments) compress more than dense mixes.
FLAC vs MP3 — which is better?
FLAC is lossless, so it preserves perfect quality but results in larger files (typically 700-1000 kbps). MP3 is lossy, achieving much smaller files (128-320 kbps) by discarding audio data humans are less likely to notice. Use FLAC for archiving and critical listening; use MP3 when file size is the priority.
Can I reduce FLAC file size further?
Beyond increasing the compression level, you can convert 24-bit files to 16-bit (saves ~25%), downsample from 96 kHz to 44.1 kHz (saves ~50%), or convert stereo to mono (saves ~50%). Note that these changes are lossy — the removed data cannot be recovered.
