.aacWhat is AAC?
Advanced Audio Coding
The streaming standard — better quality than MP3 at the same bitrate
- Format type
- Lossy compressed audio
- Standard
- ISO/IEC 13818-7 (MPEG-2 Part 7)
- Bitrate range
- 8–529 kbps (128–256 kbps recommended)
- Sample rate
- Up to 96 kHz
AAC (Advanced Audio Coding) was designed in 1997 as the successor to MP3. It achieves better audio quality than MP3 at equivalent bitrates — an AAC file at 128 kbps sounds noticeably better than an MP3 at the same bitrate. Apple adopted AAC as the default format for iTunes purchases, iPod storage, and now Apple Music streaming, making it the dominant format in the Apple ecosystem.
AAC is the default audio codec inside MP4 and MOV video files, used by YouTube for streaming, and the preferred format for Apple devices. It is supported by all modern devices and platforms. The main limitation compared to MP3 is slightly less ubiquitous support on older hardware and some non-Apple software — though this is rarely a practical concern today.
Technical Specifications
| Format type | Lossy compressed audio |
| Standard | ISO/IEC 13818-7 (MPEG-2 Part 7) |
| Bitrate range | 8–529 kbps (128–256 kbps recommended) |
| Sample rate | Up to 96 kHz |
| Channels | Up to 48 channels |
| File extension | .aac, .m4a (in MP4 container) |
| MIME type | audio/aac |
Advantages & Limitations
Advantages
- Better quality than MP3 at the same file size
- Native format for iTunes, Apple Music, and iPhone
- Default audio codec inside MP4 and MOV video files
- Used internally by YouTube and Spotify for audio streaming
- Supports up to 48 audio channels (surround sound)
- Good compatibility on all modern devices
Limitations
- Lossy — some audio quality is permanently discarded
- Slightly less compatible on older hardware than MP3
- Multiple container formats (.aac, .m4a) can cause confusion
Common Use Cases
- Apple Music and iTunes libraries
- iPhone and iPad audio storage
- Streaming platform audio delivery
- Audio track inside MP4 and MOV video files
- Podcast production for Apple Podcasts
- Game audio on Apple platforms
Compatible Software & Platforms
AAC is natively supported by:
Convert AAC Files — Free Online Tools
Convert from AAC
Convert to AAC
Frequently Asked Questions
What is a AAC file?
A AAC file is a audio file using the Advanced Audio Coding format. AAC (Advanced Audio Coding) was designed in 1997 as the successor to MP3.
What programs open AAC files?
AAC files are supported by: iPhone / iPad / Mac, iTunes / Apple Music, Android (native support), YouTube, Spotify, and most modern media players and editors.
What are AAC files used for?
Common uses include: Apple Music and iTunes libraries; iPhone and iPad audio storage; Streaming platform audio delivery.
AAC vs MP3: what is the difference?
AAC has better quality per kilobit; MP3 has broader legacy device compatibility. AAC is typically chosen for apple music and itunes libraries, while MP3 is preferred for podcast distribution to apple podcasts, spotify, and google.
How do I convert a AAC file?
Convert AAC files online for free at MediaFormatter. Upload your file, choose a target format, and download the result — no installation or sign-up needed.