MP3 vs AAC vs FLAC vs OGG: Audio Formats Compared

All audio formats trade quality against file size against compatibility. Here is the short, practical version.

MP3 — plays on everything

The oldest and least efficient of the lossy formats, but every device made in the last 25 years plays it. Choose MP3 when compatibility is the priority: car stereos, cheap players, sharing with unknown recipients. Convert anything with WAV to MP3 or M4A to MP3.

AAC / M4A — better quality per megabyte

The successor to MP3, used by YouTube, Apple Music and most streaming services. At the same bitrate it simply sounds better than MP3. Use it when the target device is modern (any smartphone).

FLAC — lossless archive

Compresses the original audio to ~50-60% without losing a single bit. The format for music collections, masters and anything you might re-encode later. Files are 5-10x larger than MP3. FLAC to MP3 is the classic "shrink my library for the phone" conversion.

OGG Vorbis and Opus — open and efficient

Opus is technically the best lossy codec today, especially for voice and low bitrates: it is what Discord, WhatsApp and Telegram use for calls. The only weakness is patchy support in older hardware. Great for podcasts and voice notes.

Rule of thumb

• Maximum compatibility → MP3
• Modern devices, streaming → AAC
• Archiving, audiophile needs → FLAC
• Voice, calls, low bandwidth → Opus