Audio conversion uses FFmpeg through the single-threaded @ffmpeg/core 0.12.10 build, licensed under GPL-2.0-or-later. FFmpeg. ffmpeg.wasm.
AAC is the audio inside most MP4 and M4A files, but sometimes you get it on its own as a bare .aac file. Some voice recorders, stream-capture tools and audio apps produce them. Plenty of older players, car stereos and web forms do not accept .aac. This free AAC to MP3 converter turns the file into an MP3 they will take. If your file ends in .m4a, use M4A to MP3 instead.
How do I convert AAC to MP3?
- Click Browse files or drag the .aac file onto the converter.
- Choose the Audio quality. Use the source's bitrate or the next step up.
- Click Convert to MP3.
- Click Download MP3.
What is an AAC file?
AAC (Advanced Audio Coding) is a lossy codec standardized by MPEG in 1997 as the successor to MP3. It is the standard audio of iPhone videos, the iTunes Store and many streaming services. A file with the .aac extension usually holds a raw AAC stream in the ADTS format: audio frames one after another, with no MP4 wrapper around them. We tested ADTS .aac files, and they convert normally.
| You have | What it is | Page |
|---|---|---|
| song.aac | Raw AAC stream (ADTS) | This page |
| song.m4a | AAC inside an MPEG-4 audio file | M4A to MP3 |
| video.mp4 | AAC plus video in an MP4 | MP4 to MP3 |
Is AAC better than MP3?
At the same bitrate, usually yes. AAC was designed to beat MP3, and at 128 kbps it tends to sound cleaner. MP3 wins on compatibility: it is older and plays on hardware that predates AAC. That is the reason to convert.
What bitrate should I use for AAC to MP3?
Because AAC is more efficient, an MP3 needs a bit more data to sound as good:
| AAC source | MP3 bitrate |
|---|---|
| 64 kbps or less, voice | 128 kbps |
| 128 kbps, music | 192 kbps |
| 256 kbps, music | 256 or 320 kbps |
In our test, one minute of 128 kbps AAC weighed 979,854 bytes as a .aac file. Its MP3 at 192 kbps weighed 1,442,002 bytes. Expect the MP3 to be somewhat bigger than the AAC; that is normal.
Will converting AAC to MP3 reduce quality?
A little, because you compress already-compressed audio again. At the bitrates above, the loss is very hard to hear. Do not convert the MP3 back to AAC later; each round trip adds loss.
Limits of the AAC to MP3 page
This page accepts .aac files only, up to 150 MB and one at a time. It does not download audio from streams or links. For M4A, MP4 or other files, use the main MP3 converter.
Frequently asked questions about AAC to MP3
Is this AAC to MP3 converter free?
Yes. It is free with no sign-up, and the conversion happens in your browser.
Is my AAC file uploaded?
No. The file stays on your device.
What is the difference between AAC and M4A?
AAC is the codec, M4A is a file that contains it. A .aac file is a bare AAC stream; a .m4a file wraps AAC in an MPEG-4 container.
Why is my MP3 bigger than the AAC file?
AAC is more efficient, so MP3 uses more data for similar sound. You convert for compatibility, not to save space.
Which bitrate should I pick?
192 kbps for a 128 kbps music file, 128 kbps for voice.
Can my car play MP3 but not AAC?
Many older car stereos and USB players only read MP3. Converting to MP3 is the simplest fix.
Convert your AAC to MP3
Choose the .aac file, pick a bitrate and download an MP3 that plays anywhere.
Other audio to MP3 converters
- M4A to MP3: AAC in an Apple audio file.
- OGG to MP3: Vorbis and Opus audio.
- WAV to MP3: uncompressed recordings.
- Audio to MP3 converter: every audio format in one place.