Convert AAC to M4A online

Your AAC file is converted to M4A right here in your browser, using FFmpeg compiled to WebAssembly. Nothing is uploaded to us, the audio never leaves your device. Quality is preserved and the download is ready in seconds.

What is an AAC file?

AAC (Advanced Audio Coding) is MP3's designed successor: at the same bitrate it preserves noticeably more detail, especially at the low bitrates where MP3 falls apart. It is the audio inside YouTube videos, M4A files and most streaming services.

AAC is everywhere modern media is: YouTube, iPhones, Android, streaming platforms. Raw .aac files are less common than AAC-inside-M4A, but they behave the same.

Why M4A?

M4A is the MPEG-4 audio container, almost always holding AAC-encoded audio. It is what an iPhone produces: Voice Memos, iTunes purchases and most Apple-ecosystem audio are M4A files.

Convert to M4A for the Apple ecosystem, or when you want noticeably better quality than MP3 at the same file size, AAC is MP3's designed successor and it shows at lower bitrates. The rare weak spot is legacy hardware: very old players and some embedded systems only understand MP3 or WAV.

Frequently asked questions

Will converting AAC to M4A lose quality?

A small, one-time generational loss is unavoidable. Both AAC and M4A are lossy, so re-encoding discards a little more detail. The converter uses high-quality settings to keep it inaudible for speech, but if you still have the original uncompressed source, converting from that instead is always better.

Is it free?

Yes, completely, with no account and no watermark. The conversion runs on your own device, so it costs us nothing to let you use it. The only limit is file size: up to 50 MB, which is what a browser can hold in memory comfortably.

Do I need to install anything, or upload my file?

Neither. It runs entirely in your browser using FFmpeg compiled to WebAssembly. Your audio is never sent to us, which is also why it works on a slow connection, only the page downloads, not your file.

Need a transcript of the audio?

Autrans also transcribes audio in Nigerian English, Pidgin, Yoruba, Hausa, Igbo, French, and Spanish.