AAC vs. MP3

Discover which music format is better for your iOS device

Illustration of sound waves and audio levels above audio player controls

 45RPM/DigitalVision Vectors/Getty Images

Many people assume that all digital music files are MP3s, but many other formats exist, including AAC. Usually, you can choose the file format in which you want to save in songs, which is particularly useful when ripping CDs in iTunes or converting high-quality, lossless files to other formats.

These two music file formats have their strengths and weaknesses, such as file size and sound quality. So, how do you choose which is better for your iPhone?

For a deep-dive look at exactly what makes an AAC music file different from an MP3 music file, check out What Makes an MP3 Different From an AAC?

Overall Findings


  • Small file size.

  • Better sound quality than MP3.

  • Not a proprietary format.

  • May not be compatible with every device.


  • Small file size.

  • Compatible with most mobile audio devices.

  • Not a proprietary file format.

  • Lower sound quality than ACC.

  • An older file format.

AAC and MP3 are the most common file types used with iPhone and iTunes. They're similar, but they differ in four important ways.

File Size: ACC for the Win

Both AAC and MP3 are compressed file formats. That means that they try to make files small by removing some hard-to-hear parts of the song while keeping the sound quality good. AAC is generally the slightly smaller file type.

AAC files are generally higher quality and slightly smaller than MP3 files of the same song. The reasons are fairly technical, but the simplest explanation is that AAC was created after MP3 and offers a more efficient compression scheme so that less audio quality is lost.

Compatibility: MP3 Works Just About Everywhere

MP3 is the most common digital music format, so you can count on virtually any device being able to play it. AAC isn't as ubiquitous, but most devices can play it, including all Apple products.

Besides AAC and MP3, Apple devices support formats like Apple Lossless Encoding, AIFF, and WAV—high-quality, uncompressed file types used to create CDs. Avoid using them unless you really know what they are and why you want them.

Despite popular belief, AAC was not created by Apple: It is not a proprietary Apple format. AAC can be used with a variety of non-Apple devices, although it is the native file format for the iTunes Store and Apple Music.

Audio Quality: The Sweet Sounds of ACC

How good the music sounds in each file format is key. It can be really tough to distinguish between AAC and MP3 files on most devices, but AAC sometimes sounds slightly better.

For a side-by-side listening test that compares AAC to MP3, read What Is the Best Format For Your Music: AAC or MP3?

Proprietary Format: It's a Toss-Up

Digital Rights Management (DRM) refers to restrictions on how you use and share your music. There's no DRM restriction on files you create, but if you're buying them from a store or downloading them from a streaming service like Apple Music, it's worth finding out if DRM is used.

Final Verdict: AAC

If you plan to stick with the iPhone, iTunes, and Apple for a long time, we recommend using AAC for your digital music. You can always use iTunes to convert AAC files to MP3 format if you decide to switch to a device that doesn't support AAC (though there aren't many such devices). In the meantime, using AAC means that your music will sound good and you’ll be able to store a lot of it.

And remember: Create AAC files only from high-quality sources like CDs. If you convert an MP3 to an AAC, you'll lose some audio quality.