Convert MP3 to AAC
We turn MP3 into AAC right in your browser — the file never goes to a server.
What you will lose
Nothing important: the target format does everything the source does.
How they differ
| MP3 | AAC | |
|---|---|---|
| Lossless | no | no |
| Lossy | yes | yes |
| Multichannel | no | yes |
| Tags | yes | yes |
| Released | 1993 | 1997 |
| Author | Fraunhofer IIS | MPEG |
MP3
Good at
- Plays literally everywhere, from a 2003 car stereo to a smart speaker
- Predictably small: an hour of speech fits in 30 MB
- Every player reads its tags, without exception
Awkward about
- Lossy, and re-encoding it again is audible
- Two channels at most — surround will not survive
- At the same size, Opus and AAC sound better
Use it when
- It has to open for anyone, on anything
- A podcast, an audiobook, a recorded lecture
- The file goes to a person, not into further processing
AAC
Good at
- Noticeably better than MP3 at the same size
- The native format for Apple gear and most phones
- Handles multichannel audio and tags
Awkward about
- Older devices and car stereos may refuse it
- Lossy — the original cannot be recovered from it
- Encumbered by patents, unlike Opus
Use it when
- Listening on a phone without wasting quality
- A voice memo, or a track pulled out of a video
- You want a balance between size and sound
Common questions
- Does the file get uploaded to a server?
- Yes, this pair needs the server: browsers cannot encode that format. The file and the result are deleted within a couple of hours and never shared.
- Will surround sound survive?
- Yes, AAC carries more than two channels — 5.1 stays 5.1.
- Can I get the original quality back afterwards?
- No. AAC is lossy, and the discarded detail cannot be recovered. Keep the original if you may still need it.
- How many files, and how large?
- Up to 10 files at a time, 200 MB each. No sign-up, no watermarks.