Convert AAC to M4A — Free Online Converter

AAC and M4A are intimately related — M4A is simply the file extension Apple uses for MPEG-4 containers that hold AAC audio. A raw AAC stream (ADTS format) lacks metadata support, chapter markers, and album art embedding. Converting to M4A wraps the AAC audio in a proper MPEG-4 container, enabling full metadata, gapless playback tags, and compatibility with iTunes, Apple Music, and every media player that expects the M4A format.

Raw AAC files (.aac extension) use the ADTS transport format, which streams audio but cannot store ID3 tags, album artwork, chapter markers, or gapless playback information. M4A containers add all of this while keeping the audio data identical. Many music players and library managers (iTunes, MusicBee, Plex) handle M4A better than raw AAC, displaying proper metadata and enabling features like bookmarking and chapter navigation.