File size
WAV is the largest by far — roughly 10 MB per minute of CD-quality stereo audio. FLAC compresses that to about 5–6 MB per minute with no loss in quality. MP3 at 192 kbps comes in around 1.4 MB per minute — roughly one-seventh the size of WAV.
Sound quality
WAV and FLAC are mathematically identical to the original recording. MP3 discards detail using a psychoacoustic model. At 192 kbps and above most listeners cannot tell it apart from the lossless source on consumer speakers. At low bitrates (64–96 kbps) MP3 starts to sound thin or 'underwater', especially on cymbals and complex music.
Compatibility
MP3 plays on everything — every browser, every phone, every car stereo since the late 1990s. WAV plays everywhere too, but the file size makes it impractical for sharing or streaming. FLAC support is excellent on desktop and Android, more limited on Apple devices and older car systems.
When to use each
Sharing a podcast, song demo, or voice memo: MP3. Editing, mixing, or sending to a producer: WAV. Archiving your music collection: FLAC.