Audio
What is an AAC file?
Updated Jul 2026
AAC (Advanced Audio Coding) is a lossy audio format built as a successor to MP3. It compresses music and other audio to a smaller file size while generally sounding better at the same bitrate. The tradeoff is the same as any lossy format: some of the original audio detail is discarded and can't be recovered.
- Extension
- .aac
- Type
- Audio
- Typically
- Apple / streaming audio
- Compression
- Lossy
Why AAC exists
AAC was standardized in the late 1990s as a follow-up to MP3, designed to squeeze more perceived audio quality out of fewer bits. Apple adopted it early and it became the default format for iTunes downloads and Apple Music, which is why so many people associate it with Apple devices.
Like MP3, AAC works by throwing away parts of the audio that human hearing is less likely to notice, then compressing what's left. The result is a much smaller file than the original recording, at the cost of some fidelity that can't be restored later.
AAC also underpins the audio in most streamed video and podcasts, so it shows up constantly even when nobody chose it directly. People usually need to convert it when a device, car stereo, or older piece of software only recognizes MP3 or WAV instead.
The trade-offs
Strengths
- Smaller files than MP3 at similar perceived quality
- Widely supported on phones, streaming services, and video
- Handles a broad range of bitrates well, from low to high quality
Watch-outs
- Lossy, so some original audio detail is permanently discarded
- A few older devices and car stereos only accept MP3 or WAV
- Re-encoding an AAC file to another lossy format degrades it further
A note on privacy
AAC files can carry embedded tags like track title, artist, album, and sometimes cover art, similar to the metadata in an MP3. That's usually harmless, but it's still information about your files leaving your machine when you use an online converter. Converting on your own computer means the audio and its tags never get uploaded anywhere.
Convert an AAC file
- Convert AAC to MP3
- Convert AAC to WAV
- Convert AAC to FLAC
- Convert AAC to M4A
- Convert AAC to OGG
- Convert AAC to WMA
Questions
How do I open an AAC file?
Most phones, media players, and streaming apps play AAC natively without any extra steps. If something refuses to open it, converting to MP3 usually solves it.
Is AAC better than MP3?
At the same bitrate, AAC generally sounds a bit clearer, which is why Apple and most streaming services use it. MP3 still wins on raw compatibility with older hardware and software.
Why does my phone save recordings or downloads as AAC?
Apple devices and many apps default to AAC because it gets better quality per megabyte than MP3. You'll run into it any time you export audio, download music, or save a voice memo.
Can I convert AAC without uploading it?
Yes. A desktop app like Morphjet converts AAC to MP3, WAV, or other formats directly on your computer, so the audio file never leaves your machine.
Morphjet opens and converts AAC and 1,800+ other formats, all on your own computer. Launching this July.