No, this isn't a "who's buried in Grant' tomb" question. Rather: How much space for apps, music, etc is available on a fresh-out-of-the-box 16GB iPad? My 64GB iPad says that its "capacity" is 58.12 GB, which suggests that almost 8GB is taken up by disk formatting and the OS. That wouldn't leave much for other stuff on a 16GB. I'm providing "pre-sales tech support" for a price-sensitive relative; any data out there? Thanks!

  • The simple pre-sales advice can be decided on how likely iTunes Match can solve a music storage issue as well as hoe much video playback / iMovie editing and video capture the owner will want. Any one of these can make the 32G model well worth the up charge. No to all, and save the money. – bmike Dec 9 '11 at 1:15
  • @bmike Why does 64 GB leaves me with 58 GB (a decrease of 8 GB) but 16 GB leaves 13 GB (a decrease of only 3 GB) What are stored there? There's root partition that's should be same size for both capacity and maybe partition table and stuff. But why would it take this much storage on a 64 GB device? – Shane Hsu Feb 14 '13 at 17:07
  • My guess is there are three items "taking up the space" My 64 GB iPad has 57.18 GB free. Why not ask a follow up question about this and link to it in chat so I can see it and respond more fully? – bmike Feb 14 '13 at 17:13

On iOS 5 you should expect to have about 13.75 GB for items you choose to store on any 16 GB iOS device. On iOS 4 it was slightly higher - slightly over 14 GB.

  • Thanks; that sounds about right. I just got off a textchat with somebody at store.apple.com, who said that only about 1 GB was taken up by the os and pre-installed apps; that strikes me as a bit low. Dunno... – Jim Miller Dec 9 '11 at 0:20
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    I would agree that the install image itself might be 1 GB, but that's different than usage when deployed and running as well as the space taken by empty directories and cushion for things like Garbage Collection / swap? / whatever else ends up taking space like music database files and such. – bmike Dec 9 '11 at 1:13

Storage device manufacturers measure capacity using the decimal system (base 10), so 1 gigabyte (GB) is calculated as exactly 1,000,000,000 bytes. The capacity of the storage media in your Mac, iPad, iPod, iPhone and other Apple hardware is measured using this decimal system. This is detailed on product packaging and online through the statement "1 GB = 1 billion bytes."

Understanding storage capacity in iPad, iPhone, iPod

When you view the storage capacity of your iPod, iPhone, iPad, or other electronic devices within its operating system, the capacity is reported using the the binary system (base 2) of measurement. In binary, 1 GB is calculated as 1,073,741,824 bytes.

For example: The way decimal and binary numeral systems measure a GB is what causes a 32 GB storage device to appear as approximately 28 GB when detailed by its operating system, even though the storage device still has 32 billion bytes (not 28 billion bytes), as reported.

You can see this difference if you look at how your computer summarizes the capacity of your iPod, iPad, or iPhone’s storage when the device is connected to your computer. You will also see this difference in the About menu on your iPod, iPad, or iPhone. The important point to understand is that the available storage capacity is the same no matter which system (decimal or binary) is used. Nothing is missing.



On iOS 6.0.1, iPad 4, I started with 13.3 GB. It depends on your iCloud sync as well. But as I see, you need at least 2.5 GB of free space which means that you will have a number around 13.5 too.

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