MP3 to M4A

Convert MP3 to M4A in three steps

1. Choose one or more MP3 files, or try the included sample.
2. Pick your AAC bitrate and press Convert to M4A. Keep this tab open while it works.
3. Listen to the preview and save individual files or download the batch as a ZIP.

When M4A is the better format

Apple Music, iTunes on Windows, iPhone and iPad, and many podcast and video editors treat M4A as a first-class format. AAC, the codec inside, was designed as the successor to MP3 and is more efficient: encoded from the same source, it usually sounds a little better at the same bitrate, or similar at a lower one. That is why M4A is common for music libraries on phones. Converting an existing MP3 does not unlock that benefit, though, because the MP3 has already lost detail. The main reason to convert is that an app, a device, or a workflow asks for M4A.

What happens during conversion

The converter decodes the MP3 to raw audio, encodes AAC-LC with the encoder built into your browser, and wraps the result in an MPEG-4 audio file with the .m4a extension. This is lossy to lossy, so the result is never better than the MP3 and is slightly worse at the same bitrate. Keep your original MP3. If you need an uncompressed copy for editing instead, the MP3 to WAV converter is the right tool, and the MP3 to M4R page makes an iPhone ringtone from the same kind of file.

Choosing a bitrate

192 kbps is the default and a safe match for most music MP3s. Choose 256 kbps when the source MP3 is 256 or 320 kbps and you want to keep as much as possible. 128 kbps suits speech, audiobooks, and lectures, and 96 kbps is fine for voice recordings you only need to understand. A 192 kbps M4A takes about 1.4 MB per minute. Going above the bitrate of the original MP3 adds size but no quality, so there is little reason to choose 256 kbps for a 128 kbps source.

Browser support

AAC encoding depends on your browser. Chrome, Edge, and Safari on desktop include an AAC encoder, and so do browsers on recent iPhones and Android phones. Firefox does not have one, so the page tells you and suggests another browser instead of failing silently. You can convert several MP3s in one batch, listen to each M4A, and download them one at a time or as a ZIP. Files stay on your device, with no account, no upload, and no watermark.