Convert MP3 to AAC
Convert MP3 to AAC format instantly in your browser. AAC is the standard audio format for iPhone, iPad, iTunes, and most streaming services — better quality than MP3 at the same file size. No upload needed.
Drag 'n' drop files here, or
click to select files
.mp3
Drop your files and click Convert to get AAC
//when_to_use
When to Convert MP3 to AAC
- Converting a podcast MP3 master to AAC for submission to Apple Podcasts Connect, which recommends AAC
- Preparing a ringtone MP3 to AAC (M4R) format for use on iPhone via iTunes
- Converting an MP3 background music track to AAC for use in an iOS app's asset bundle via Xcode
- Uploading a music track to YouTube Music or Apple Music for Artists which expects AAC in an M4A container
- Converting MP3 voice memos to AAC to reduce storage on an iPhone or iCloud music library
//comparison
MP3 vs AAC
| Property | MP3 | AAC |
|---|---|---|
| Compression | LAME MP3 (lossy) | AAC (lossy) |
| Typical file size (4 min song) | 3-5 MB | 3-5 MB |
| Quality at same bitrate | Baseline | ~20% better |
| iPhone/iOS support | Native | Native (preferred) |
| YouTube/streaming | Supported | Preferred codec |
| iTunes/Apple Music | Supported | Native format |
//how_it_works
How It Works
Drop your MP3 files
Drag and drop or select MP3 audio files. Any bitrate, stereo, or mono configuration is supported. First use loads FFmpeg WASM (~30MB).
FFmpeg decodes MP3 to PCM
FFmpeg WASM decodes the MP3 frames to raw PCM audio samples using libmpg123. All processing happens locally in your browser — no upload.
AAC encoding at 192kbps
The FFmpeg native AAC encoder compresses the PCM at 192kbps using temporal noise shaping and psychoacoustic masking for Apple-quality output.
Download AAC files
Your AAC files are ready for iPhone, iPad, iTunes, YouTube Music, or any Apple ecosystem app that expects native AAC audio.
// under the hood
MP3 uses the LAME psychoacoustic model over MDCT sub-bands with Huffman coding. AAC uses a more flexible MDCT implementation with better psychoacoustic masking, temporal noise shaping (TNS), and perceptual noise substitution (PNS). Our converter uses FFmpeg WASM to decode MP3 via libmpg123 and re-encode with the native FFmpeg AAC encoder (libavcodec aac) at 192kbps constant bitrate, output as ADTS AAC.
//faq
Frequently Asked Questions
- What is AAC format?
- AAC (Advanced Audio Coding) is a lossy audio compression standard developed by Fraunhofer, Dolby, AT&T, and Sony as the successor to MP3. It's the default audio format on iPhone, iPad, Apple TV, iTunes, YouTube, and most streaming services. AAC achieves better sound quality than MP3 at the same bitrate due to improved psychoacoustic modeling and more flexible block sizes.
- Why convert MP3 to AAC?
- AAC is the native format for the Apple ecosystem — converting to AAC ensures your audio plays without any compatibility issues on iPhone, iPad, Apple Watch, and via AirPlay. It's also the preferred format for YouTube uploads, WhatsApp voice messages, and many streaming workflows that expect AAC in an M4A or MP4 container.
- Does MP3 to AAC improve audio quality?
- No — because MP3 is already a lossy format, converting to AAC won't restore lost audio data. You'll get a file that sounds similar but with slight additional transcoding artifacts. The real benefit is format compatibility, not quality improvement. If you have lossless sources (WAV, FLAC), convert from those for the best AAC quality.
- What container does the AAC file use?
- Our converter outputs a raw AAC bitstream in an ADTS (Audio Data Transport Stream) container with a .aac file extension. This is universally supported by Apple devices and players. If you need an M4A (MPEG-4 audio container), most audio editors like Audacity or GarageBand can rewrap ADTS AAC to M4A without re-encoding.
- Is this conversion free and private?
- Yes. All conversion runs locally in your browser via FFmpeg WebAssembly. Your MP3 files never touch our servers — zero upload, zero logging, zero storage. It's completely free with no account required.
//related_converters
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