AAC vs. MP3: Which to Choose for iPhone and iTunes

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Many people assume that all digital music files are MP3s, but that's not necessarily true. You can actually choose the file format you want songs to be saved in (in most cases). This is particularly useful when ripping CDs in iTunes or converting high-quality, lossless files to other formats.

Each music file format has different strengths and weaknesses—generally involving size and sound quality—so how do you choose which is best for you?

Why Different File Types Matter

AAC and MP3 are probably the most common file types used with the iPhone and iTunes. They're pretty similar, but they're not identical. They differ in four ways that should be important to you:

  • File size—Both AAC and MP3 are compressed file formats, meaning they balance a song sounding good with making it take up less space on your device. AAC is generally slightly smaller.
  • Compatibility—MP3 is the most common digital music format, so you can count on virtually any device being able to play it. AAC is slightly less ubiquitous, but most devices can play it these days, including all Apple products.
  • Audio quality—How good the music sounds in each file format is key. It can be really tough to distinguish between the two on most devices, but AAC sometimes sounds slightly better.
  • DRM—Digital Rights Management, restrictions put on how you use and share your music, can apply to either AAC or MP3. There's no DRM on files you create, but if you're buying them from a store, it's worth finding out if it's present.

Common Music File Types

In addition to the two most common file types used on Apple devices, AAC and MP3, these devices also support formats like Apple Lossless Encoding, AIFF, and WAV. These are high-quality, uncompressed file types used for CD burning. Avoid using them unless you really know what they are and why you want them.

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

Despite popular belief, AAC was not created by Apple and is not a proprietary Apple format. AAC can be used with a wide variety of non-Apple devices, though it is also the native file format for iTunes. While AAC is slightly less widely supported than MP3, virtually any modern media device can use it. 

Common iPhone Music File Formats Compared

Here’s a guide to deciding what file type you’ll want to use in iTunes. Once you’re done reading this, check the step-by-step guide to changing iTunes settings to use the file format you want.

AAC AIFF Apple Lossless MP3

Small file size

Higher quality sound
than MP3

Highest quality sound

Highest quality sound

Small file size

More compatible: works with virtually every portable audio player and cell phone


Slightly less compatible; Works with Apple devices, most Android phones, on the Sony PlayStation 3 and PlayStation Portable, and some cell phones

Somewhat less compatible

Larger files than AAC or MP3

Slower encoding

Older format

Less compatible; Only works with iTunes and iPod/iPhone

Larger files than AAC or MP3

Slower encoding

Newer format

Slightly lower sound quality than AAC

Proprietary? No Yes Yes No

Recommendation: AAC

If you plan to stick with iTunes and an iPod or iPhone for a long time, we recommend using AAC for your digital music. You can always convert AAC to MP3 using iTunes if you decide to switch to a device that doesn't support AAC. In the meantime, using AAC means your music will sound good and you’ll be able to store a lot of it.

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