AAC to FLAC Converter
Convert AAC audio files to FLAC (Free Lossless Audio Codec) format for perfect quality preservation. Choose compression level to balance file size and encoding speed while maintaining lossless quality. Professional-quality audio conversion powered by FFmpeg, all processing happens securely in your browser.
Recommended Settings
For Archival
- •Compression level 5-8 for smaller files
- •44.1 kHz for music (CD quality)
- •Perfect quality preservation
For Quick Conversion
- •Compression level 0-3 for faster encoding
- •Still completely lossless quality
- •Larger file sizes
Pro Tips
- •All compression levels are lossless - higher levels just take longer
- •FLAC files are typically 40-50% of original uncompressed size
- •Cannot improve quality beyond the source AAC file
Most Popular
Most users choose compression level 5 with 44.1 kHz for balanced results
When to Use This Tool
FLAC is lossless, preserving perfect audio quality. Ideal for archiving music collections without any quality loss.
Recommended: Compression level 5-8
Convert AAC to FLAC for high-fidelity playback on quality audio equipment. Perfect for critical listening.
Recommended: 44.1 kHz or 48 kHz
Use FLAC for lossless storage of audio masters and production files with perfect quality preservation.
Recommended: Compression level 5
How It Works
Upload your AAC audio file
Choose compression level and sample rate
FFmpeg processes lossless conversion in-browser
Download your converted FLAC file
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by FFmpeg.wasm (WebAssembly) for optimal performance on modern browsers.
Open Source
Built with verified, open-source libraries. Fully transparent.
Frequently Asked Questions
What is FLAC?
FLAC (Free Lossless Audio Codec) is a lossless compression format that preserves perfect audio quality while reducing file size by about 40-50%. Unlike MP3 or AAC, no quality is lost in FLAC.
What does compression level mean?
Compression level (0-8) controls how much the file is compressed. Higher levels create smaller files but take longer to encode. Level 5 offers a good balance. Quality remains lossless at all levels.
Will I get better quality than the AAC source?
No. FLAC is lossless, but it can't recover quality lost in the original AAC encoding. It preserves the AAC quality perfectly without further degradation.
What devices support FLAC?
Most modern devices support FLAC including smartphones, computers, and many audio players. However, some older devices may not support it.
How much larger will FLAC files be?
FLAC files are typically 2-3x larger than AAC files since they're lossless. The exact size depends on the compression level and audio complexity.