M4A vs MP3
M4A usually sounds better than MP3 at the same size. MP3 plays on more devices. Here’s how to choose.
| Feature | M4A | MP3 |
|---|---|---|
| Codec | AAC (or Apple Lossless) | MP3 |
| Quality at 128 kbps | Very good | Good |
| Lossless option | Yes (ALAC) | No |
| Typical use | iPhone voice memos, Apple Music, iTunes | Music downloads, podcasts, everywhere |
| Compatibility | Most modern devices | Virtually all devices |
What's inside an M4A
M4A is an MPEG-4 container holding only audio. Usually that audio is AAC, Advanced Audio Coding, which was designed as MP3's successor and achieves better quality at the same bitrate. Some M4A files contain Apple Lossless (ALAC) audio instead, which is lossless like FLAC.
iPhones save voice memos as M4A, iTunes and Apple Music use AAC, and many Android recorders and apps also produce M4A files.
Quality and size
At high bitrates such as 256 kbps, both formats sound excellent and most listeners can't tell them apart. The difference shows at lower bitrates. A 128 kbps AAC file generally sounds cleaner than a 128 kbps MP3, with fewer swishy artefacts, so you can use a lower bitrate for the same perceived quality and save space.
For speech, AAC also does better at very low bitrates, which is why it suits voice memos and podcasts.
Compatibility
MP3 is supported by essentially everything with a speaker, including old car stereos, cheap MP3 players, DJ software, and websites that only accept MP3 uploads. M4A is supported by all modern phones, computers and browsers, but some older hardware and a few apps and services still reject it.
Should you convert M4A to MP3?
Convert only when you need to, because converting from one lossy format to another loses a little quality. If you do, choose a bitrate at least as high as the original; for voice memos, 128 kbps mono is plenty. Keep the original M4A if you might need it later.
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Questions
Is M4A better than MP3?
At the same bitrate, AAC in M4A usually sounds better. MP3 is more widely compatible.
Does converting M4A to MP3 lose quality?
Slightly, since both are lossy. At 192 kbps or more, the difference is very hard to hear.
Why are my voice memos M4A?
iPhones record voice memos as AAC audio in an M4A file to keep them small and clear.
Can Windows play M4A?
Yes. Media Player on Windows 10 and 11 plays M4A files.