What is AAC?
Advanced Audio Coding
AAC is the successor to MP3, offering better sound quality at the same bitrate. It's the default format for iTunes, YouTube, and most streaming services — a sweet spot between size and fidelity.
History of AAC
AAC (Advanced Audio Coding) was standardized in 1997 as the official successor to MP3. It delivers better quality at the same bitrate, especially at lower bitrates, and was adopted by Apple as the default for iTunes and the iPod. Today AAC powers YouTube, most streaming services, and TV broadcasting.
Technical specs
- Format name
- Advanced Audio Coding
- File extension
- .aac
- MIME type
- audio/aac
- Category
- Audio
- Compression
- Lossy compression
When to use AAC
Reach for AAC when you need apple music and itunes libraries, youtube and streaming services, mobile app audio, broadcast and satellite radio. It excels at these scenarios because better quality than mp3 at the same bitrate and wide modern device support.
Pros
- +Better quality than MP3 at the same bitrate
- +Wide modern device support
- +Efficient for streaming
When to avoid AAC
Avoid AAC when still lossy compression, and slightly less universal than mp3. In those cases, look at the alternatives below.
Cons
- −Still lossy compression
- −Slightly less universal than MP3
- −Some licensing restrictions
Common uses for AAC
- Apple Music and iTunes libraries
- YouTube and streaming services
- Mobile app audio
- Broadcast and satellite radio
Alternatives to AAC
MP3 is more universally supported, but lower quality at the same bitrate. FLAC for lossless.
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AAC — Frequently Asked Questions
Is AAC still used in 2026?
Is AAC still used in 2026?
Yes, AAC is actively used. Apple Music and iTunes libraries keeps it relevant.
Can I open a AAC file on my phone?
Can I open a AAC file on my phone?
Yes, especially on Apple devices.
Why is my AAC file so different in size from other files?
Why is my AAC file so different in size from other files?
AAC file sizes depend on encoder settings (bitrate, resolution, quality). For smaller files, re-encode at a lower bitrate or convert to a more compressed format.
Can I convert AAC to another format for free?
Can I convert AAC to another format for free?
Yes — Zen Convert converts AAC files to every other audio format we support, for free, in your browser. No signup, no watermark.
Is AAC open-source?
Is AAC open-source?
AAC is standardized but its patents are still active. Commercial implementations require licensing.