Audio
Turn your MP3 files into AAC in seconds. Everything happens in your browser: nothing is uploaded to any server.
Drag your files here
Or paste them with Ctrl+V. They never leave your device.
It loses some quality with each re-encode and, at the same size, sounds worse than AAC or Opus. As AAC it sounds better than an MP3 of the same size.
MP3 compresses sound lossily, removing what the ear barely notices, so a song takes just a few megabytes.
Strengths: Any phone, car, speaker, player or program plays it, however old.
Limits: It loses some quality with each re-encode and, at the same size, sounds worse than AAC or Opus.
AAC is the lossy audio codec that replaced MP3; this file is “raw” AAC, without a container (ADTS).
Strengths: At the same size it sounds better than an MP3 and almost every device understands it.
Limits: Without a container it holds no artwork or tags, and some programs prefer M4A.
No. The MP3 to AAC conversion runs entirely in your browser, with code downloaded from this site and executed on your device. You can check it in the Network tab of the developer tools or by going offline after the page loads.
A little, because AAC is lossy; at 192 kbps or more the difference is hard to hear.
Up to 2 GB on desktop and 500 MB on mobile (less on low-memory devices), and up to 12 hours of audio on desktop. If it is over, you are told before it starts.
Yes. Drop as many MP3 files as you like: several are converted at the same time, depending on your processor cores, and when they finish you can download each AAC or all of them in a ZIP.