For very large apps, such a GPS apps, the app store will decline updating an app if you don't have enough free space.

How much free space is needed?

For instance, I have a GPS navigation app that is currently using 1.8GB on my iPad. The update is 1.43GB. I have 1.9GB free.

The update would fit into the free space, but it still doesn't allow it. Perhaps it downloads it, then installs it before deleting the old one, meaning you'd need twice as much space in order to install it. It might even require more space if it then copies user data from the old app into the new one before deleting the old one and the installation file.

Having as much free space as the app takes isn't enough - so how much is required? Is 2*update enough, or will I need more free space?

  • The workarounds, for now, are to use iTunes, or to delete the app first, then reinstall it. Both are less than ideal, but work for those very large apps that one needs. – Adam Davis Apr 24 '12 at 18:05
  • Also can't wait for Apple to introduce differential updates. For some apps it won't matter, but for others it would make a huge difference since often very little changes from one version to the next, especially the media and artwork, which often dwarfs the code in storage space. – Adam Davis Apr 24 '12 at 18:06
  • @AndrewLarsson Yes, I still consider it unanswered. I don't know if we'll get a definitive answer though, given that we're trying to peek inside Apple's walled garden. But I'll accept your answer anyway. – Adam Davis Oct 19 '13 at 16:14
  • I like @DanielJames's post better than my own. It's definitive, up with the times, and precise. Good choice in making it the accepted answer. – Andrew Larsson Oct 31 '13 at 23:20

Apps are submitted as .ipa files which is really just a zipped container of a .app file. In fact, you can simply unzip a .ipa file to see its true size.

Apps in the App Store are listed by their compressed size, and will need to be uncompressed after installing.

As of iOS 6, updates to apps only include files that have been changed. As of iOS 7, updates to apps only include changes to changed files.

So, I guess to answer the question directly, for any given app you would need: Free space to store the compressed app update file, free space to store the uncompressed app update file, and space currently being used by the app and all its data/caches.


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  • Very good information on the changes that have made installing apps easier on downloads and on the filesystem. – bmike Oct 30 '13 at 1:53

From my experience, it can be anywhere from one times to a tad over three times the amount of space that the app claims to take up once installed. I can't confirm this next hypothesis, but it seems to not be linear (the bigger the app, the more times the amount of space you need). For example, I've had times where I've had almost no space left on my device, and I had no problems with updates. I've also had the flip-side occur. Infinity Blade was the culprit. The App Store says it takes 595 MB, and I had 2 GB free on my device, but it wouldn't let me update it, for I needed to "try deleting some photos or videos." I finally ended up getting a little under 2.5 GB of free space before it installed. It most likely depends on the types of files and such, but I've only taken this information from my own observation. Take what you like, but it's worth something.

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