M4A to MP3 Converter

M4A is the audio format of iTunes, Apple Music downloads, GarageBand exports and iPhone voice memos. Some car stereos, older MP3 players and web forms only accept MP3, so this tool converts M4A to MP3 inside your browser, keeping the title, artist, album and cover art. Nothing is uploaded.

How to use this tool

1. Choose one or more M4A files (M4B audiobooks and AAC files work too).
2. Pick the MP3 bitrate: 192 kbps keeps music sounding the same, 128 kbps is plenty for voice memos.
3. Keep "Keep tags" on to carry over title, artist and cover.
4. Press Calculate and download the MP3s.

Formula

MP3 size ≈ bitrate (kbps) × 1000 ÷ 8 × length (s)

AAC audio in M4A is decoded by the browser (Chrome, Edge and Safari decode it natively) and encoded with LAME. Apple Lossless files and anything the browser cannot decode go through the ffmpeg engine, a one-time download of about 30 MB.

Example

A 2-minute voice memo is about 1 MB as M4A. Converted at 128 kbps it becomes 128,000 ÷ 8 × 120 = 1.92 MB of MP3, and at 64 kbps in mono about 0.96 MB.