What Is FLAC?

How it works

Think of FLAC like a ZIP file for audio. It compresses the raw audio data into a smaller package — typically 40–60% of the original WAV size — but when you play or decode it, the output is exactly identical to the source. No data is permanently removed.

This is different from MP3, which achieves compression by permanently deleting audio frequencies. With FLAC, the compression is fully reversible. Converting FLAC to WAV gives you the exact original audio. Converting FLAC to MP3 does cause quality loss, because you are then applying lossy compression to a lossless source.

Common uses

• —Archiving music collections in full quality
• —Hi-fi listening on dedicated music players or home audio systems
• —Storing original recordings before distribution
• —Audio enthusiast communities and lossless music platforms

Strengths

• +Lossless — identical audio quality to the original
• +Significantly smaller than WAV — 40–60% size reduction with no quality trade-off
• +Open source and royalty-free
• +Supports high bit depths (up to 32-bit) and high sample rates
• +Supports metadata tags (artist, album, track info)

Weaknesses

• −Not supported on iPhone or iTunes without a third-party app
• −Car stereos, many Bluetooth devices, and older hardware often cannot play FLAC
• −Still much larger than MP3 — not practical for sharing or streaming
• −Not supported by all streaming platforms and upload tools

Compatibility

FLAC plays natively on Android, Linux, VLC, and most PC-based music players (foobar2000, Winamp, MusicBee). It is supported in Windows Media Player on Windows 10 and later, and in macOS through third-party apps.

It does not play natively on iPhone or in iTunes. Apple uses ALAC (Apple Lossless) instead, which is stored in M4A containers. If you need lossless audio on an Apple device, ALAC is the alternative — or convert FLAC to M4A.

When to use FLAC

• —Archiving music in full quality on a computer or NAS drive
• —Playing music on a device you know supports FLAC
• —Storing masters before you create distribution copies

When to avoid FLAC

• —Sharing audio — convert to MP3 first, FLAC files are too large and not universally playable
• —Playing on an iPhone or Apple device (use M4A with ALAC encoding instead)
• —Uploading to streaming platforms — they transcode to their own format anyway