What is M4A?
M4A is an audio file in the MP4 container, usually with AAC compression. It’s used by iPhone voice memos, Apple Music/iTunes downloads, and many recording apps. M4A sounds great at small sizes, but some car stereos, older MP3 players, editing tools and websites only accept MP3. MP3 is the most universally supported audio format.
What to expect
Converting from AAC to MP3 means re-encoding one lossy format into another. For voice memos and normal listening that’s not audible. File size stays in a similar range. Songs with Apple DRM protection (old iTunes purchases) can’t be converted.
How to convert
Drop your M4A above, MP3 is preselected, click “Convert” and download. FFmpeg runs inside your browser, so your recordings stay on your device.