How much, or how many files, can an iPhone, iPad or iPod hold? What is its real storage capacity? And why does my 128GB iPhone report a capacity of 114GB when I plug it into iTunes? Am I getting ripped off?

We wouldn't call it a ripoff (although two people suing the company evidently think differently), since Apple puts "actual formatted capacity less" in the small print. But it is a bit confusing. In fact, there are a few different reasons why iPhones, iPads and iPods report a different formatted storage capacity to the one that is advertised by Apple on its website, and we'll go through them in this article. We also detail the true storage capacity of each model of iPhone, iPad and iPhone - explaining this in real terms, so that you know how many films, music tracks, photos, apps and so on your device can hold.

Read next: iPad buying guide 2016 | iPhone buying guide 2016 | iPod buying guide 2016

Before we start, here's the reported capacities we've been seeing for each of the four current storage tiers for iOS devices. Bear in mind that these are approximate (we've seen some variation between models and versions of iOS), but they give an idea of the shortfall you should be expect from the advertised storage capacity.

  • 128GB: approx. 114GiB
  • 64GB: approx. 56.5GiB
  • 32GB: approx. 27.5GiB
  • 16GB: approx. 11.5GiB

You'll notice that I've used the unit 'GiB', or gibibyte, even though iTunes clearly uses the unit GB. I'll explain why this is, and the difference between the two, in the next section.

Why is my iPhone/iPad/iPod's true formatted storage capacity different to the advertised capacity: Gigabytes and gibibytes

The principle reason why iTunes is reporting a different capacity to the one you thought you were getting - and the one that Apple highlights on its website, since it reflects more favourably on the company - is the difference in the way these things are measured. In some contexts it's measured using the decimal system, and in others using binary, and it can make the same amount of storage seem different, when it's really the same.

Here's how Apple explains the difference:

"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.

"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."

Technically speaking we would differ slightly from Apple's explanation, which doesn't explain that two different units are being used here. A gigabyte, shortened to GB, is equal to 1,000,000,000 bytes as explained. But the binary version of a gigabyte is known as a gibibyte and shortened to GiB; this is equal to 1,073,741,824 bytes.

That might not sound like a huge difference, but this alone would result in 128GB of storage being reported as 119.2GiB, 64GB as 59.6GiB, 32GB as 29.8GiB and 16GB as 14.9GiB. Still, it's not quite enough to account for the discrepancies we saw above.

Why is my iPhone/iPad/iPod's true formatted storage capacity different to the advertised capacity: iOS, and preinstalled apps

A factor that reflects less favourably on Apple*, is the space taken up by the iOS operating system software, and the preinstalled (and officially undeletable) apps that Apple pops on your device in the factory: Mail, Safari, Phone, Messages and so on. These account for the remaining 'missing' storage.

In fact you can delete some of the preinstalled apps and thereby reclaim a certain amount of storage space, but you'll need to jailbreak your device to do so, won't gain a huge amount of storage and will miss out on a set of apps that are rarely the best of their type but are always the best integrated into iOS. And with a few exceptions (Stocks, for example), you'll end up installing a replacement app which will take up space too.

Still, if you're keen enough to go ahead, read our article that explains how to delete any app from an iPad or iPhone.

* This also applies to mobile devices made by other manufacturers, who will also preinstall an OS and other pieces of software without subtracting them from the rated storage capacity. Yet most other firms let you delete at least some of the preinstalled apps, even if you're always going to need an OS.

The true formatted storage of each iPhone, iPad and iPod model: How many films, apps, photos and music tracks will fit on my iOS device?

Apple's various mobile devices - its iPads, iPhones and iPod models - are available in a variety of storage capacities for a variety of prices. But it's hard to know which one is right for you, and how much storage you will need. It's all very well saying an iPad can hold up to 128GB, for example, but what does that mean in practice? How many songs, photos, app or movies can each iPad, iPhone or iPod hold?

For those who are interested in finer detai, we explain how we arrived at these figures later in the article.

iPhone 6s Plus (128GB model): approx. 114GiB, or 122.4GB. 30,600 songs OR 81 films OR 229 TV shows OR 19,125 photos OR 4,080 apps OR a combination of these
iPhone 6s Plus (64GB model): approx. 56.5GiB, or 60.7GB. 15,175 songs OR 40 films OR 113 TV shows OR 9,484 photos OR 2,023 apps OR a combination of these
iPhone 6s Plus (16GB model): approx. 11.5GiB, or 12.3GB. 3,075 songs OR 8 films OR 23 TV shows OR 1,921 photos OR 410 apps OR a combination of these

iPhone 6s (128GB model): approx. 114GiB, or 122.4GB. 30,600 songs OR 81 films OR 229 TV shows OR 19,125 photos OR 4,080 apps OR a combination of these
iPhone 6s (64GB model): approx. 56.5GiB, or 60.7GB. 15,175 songs OR 40 films OR 113 TV shows OR 9,484 photos OR 2,023 apps OR a combination of these
iPhone 6s (16GB model): approx. 11.5GiB, or 12.3GB. 3,075 songs OR 8 films OR 23 TV shows OR 1,921 photos OR 410 apps OR a combination of these

iPhone 6 Plus (64GB model): approx. 56.5GiB, or 60.7GB. 15,175 songs OR 40 films OR 113 TV shows OR 9,484 photos OR 2,023 apps OR a combination of these
iPhone 6 Plus (16GB model): approx. 11.5GiB, or 12.3GB. 3,075 songs OR 8 films OR 23 TV shows OR 1,921 photos OR 410 apps OR a combination of these

iPhone 6 (64GB model): approx. 56.5GiB, or 60.7GB. 15,175 songs OR 40 films OR 113 TV shows OR 9,484 photos OR 2,023 apps OR a combination of these
iPhone 6 (16GB model): approx. 11.5GiB, or 12.3GB. 3,075 songs OR 8 films OR 23 TV shows OR 1,921 photos OR 410 apps OR a combination of these

iPhone 5s (32GB model): approx. 27.5GiB, or 29.5GB. 7,375 songs OR 19 films OR 55 TV shows OR 4,609 photos OR 983 apps OR a combination of these
iPhone 5s (16GB model): approx. 11.5GiB, or 12.3GB. 3,075 songs OR 8 films OR 23 TV shows OR 1,921 photos OR 410 apps OR a combination of these

What's the true storage capacity of an iPad?

iPad Pro (128GB model): approx. 114GiB, or 122.4GB. 30,600 songs OR 81 films OR 229 TV shows OR 19,125 photos OR 4,080 apps OR a combination of these
iPad Pro (32GB model): approx. 27.5GiB, or 29.5GB. 7,375 songs OR 19 films OR 55 TV shows OR 4,609 photos OR 983 apps OR a combination of these

iPad Air 2 (128GB model): approx. 114GiB, or 122.4GB. 30,600 songs OR 81 films OR 229 TV shows OR 19,125 photos OR 4,080 apps OR a combination of these
iPad Air 2 (64GB model): approx. 56.5GiB, or 60.7GB. 15,175 songs OR 40 films OR 113 TV shows OR 9,484 photos OR 2,023 apps OR a combination of these
iPad Air 2 (16GB model): approx. 11.5GiB, or 12.3GB. 3,075 songs OR 8 films OR 23 TV shows OR 1,921 photos OR 410 apps OR a combination of these

iPad Air 1 (32GB model): approx. 27.5GiB, or 29.5GB. 7,375 songs OR 19 films OR 55 TV shows OR 4,609 photos OR 983 apps OR a combination of these
iPad Air 1 (16GB model): approx. 11.5GiB, or 12.3GB. 3,075 songs OR 8 films OR 23 TV shows OR 1,921 photos OR 410 apps OR a combination of these

iPad mini 4 (128GB model): approx. 114GiB, or 122.4GB. 30,600 songs OR 81 films OR 229 TV shows OR 19,125 photos OR 4,080 apps OR a combination of these
iPad mini 4 (64GB model): approx. 56.5GiB, or 60.7GB. 15,175 songs OR 40 films OR 113 TV shows OR 9,484 photos OR 2,023 apps OR a combination of these
iPad mini 4 (16GB model): approx. 11.5GiB, or 12.3GB. 3,075 songs OR 8 films OR 23 TV shows OR 1,921 photos OR 410 apps OR a combination of these

iPad mini 2 (32GB model): approx. 27.5GiB, or 29.5GB. 7,375 songs OR 19 films OR 55 TV shows OR 4,609 photos OR 983 apps OR a combination of these
iPad mini 2 (16GB model): approx. 11.5GiB, or 12.3GB. 3,075 songs OR 8 films OR 23 TV shows OR 1,921 photos OR 410 apps OR a combination of these

iPod touch (128GB model): approx. 114GiB, or 122.4GB. 30,600 songs OR 81 films OR 229 TV shows OR 19,125 photos OR 4,080 apps OR a combination of these
iPod touch (64GB model): approx. 56.5GiB, or 60.7GB. 15,175 songs OR 40 films OR 113 TV shows OR 9,484 photos OR 2,023 apps OR a combination of these
iPod touch (32GB model): approx. 27.5GiB, or 29.5GB. 7,375 songs OR 19 films OR 55 TV shows OR 4,609 photos OR 983 apps OR a combination of these
iPod touch (16GB model): approx. 11.5GiB, or 12.3GB. 3,075 songs OR 8 films OR 23 TV shows OR 1,921 photos OR 410 apps OR a combination of these

How many files can an iPhone, iPad or iPod hold?

Okay, how did we come up with these numbers? Let's look at each file type, and how much storage space it takes up ion average. We'll also consider what can influence its size.

Music file sizes: How many songs can an iPhone, iPad or iPod hold?

This depends most importantly on the quality of files you use: high-quality song files take up more space (but sound better, assuming the speakers you put them through are also good enough to do them justice), but also on the file format and whether you go for lossy or lossless sound. A single song encoded as an mp3 at a bitrate of 128kbps - a fairly respectable but not particularly high bitrate - takes up about 1MB per minute, so let's assume an average of 4MB per song. That's what Apple has used in the past to create estimates for the iPods.

But you may well find songs are drastically larger than that. If you buy songs from iTunes, for instance, the standard bitrate is 256kbps, which means such tracks are on average twice as large. And longer tracks can catch you out too, if you're into dance music or classical, for example.

Movie file sizes: How many films can an iPhone, iPad or iPod hold?

As with music, there are many file formats that can be used for video, and this will cause file sizes to vary substantially. Again, we'll use Apple's standard, which is H.264 1.5Mbps video at a resolution of 640x480, with 128kbps audio. This translates into a file size of 800MB per hour. Slashfilm reckons the average length of a Hollywood film is 110 minutes, which would be about 1.5GB. A 40-minute TV episode would be about 533MB.

Read next: How to delete photos from your iPhone

Photo file sizes: How many photos can an iPhone, iPad or iPod hold?

This depends on the resolution of the image - which in the case of photos is a function of the number of megapixels on the camera that took the shot. Apple estimates an average of 6.4MB per photo for its advertised capacities, but you may find they are smaller, particularly if taken on older models of iPhone or iPad themselves - the iPad Air 1's rear-facing camera, for instance, has a rating of 5 megapixels, and photos taken with this are likely to take up a little over 1MB. Screenshots taken with iPad games might be more like 2MB to 3MB.

Again, though, we'll stick with Apple's standards for ease of comparison with the iPod numbers.

App file sizes: How many apps and games can an iPhone, iPad or iPod hold?

iOS app (and game) sizes can vary enormously. My iPhone currently holds 39 apps taking up 2.2GB, which works out at an average of 56MB. My iPad Air has 133 apps taking up 53.35GB, a far higher average of 401MB, but this is skewed by the fact that I do most of my gaming on the iPad and games - particularly high-end games, which I love - take up lots of space. And by a couple of apps that are exceptionally large because of the many smaller documents they contain.

You should bear in mind, you see, if you're looking through an existing device's 'About' menu to see what you're storing and how much space it's taking up, that many apps are rated as taking up the space allocated to documents they let you view - a comic viewer app with masses of comics in it, for instance, might look like a huge app, but would be far smaller with a sensibly sized library.

The iPhone therefore probably gives us a fairer estimate of average app size, and indeed the average across all users (rather than focusing on a tech journalist with a tendency to download high-end apps for testing) is probably lower still. In October 2012 ABI Research reported that the average iOS app was 23MB. The averages are likely to have increased further since then, so we will use a very rough estimate of 30MB per app. But gamers should expect their favourite apps to take up considerably more space.

Other file sizes: How many files and documents can an iPhone, iPad or iPod hold?

We won't go through the average size of every single file or document that an iOS device can store, but here are some sample sizes for extremely approximate storage visualisation:

  • pdfs: About 300KB to 500KB is about average for a two-page pdf.
  • Comics: a 50-page comic stored as a .cbr file seems to average between 10MB and 20MB on our system, but these things vary enormously. Our version of The Killing Joke, which is 64 pages long and stored as a .cbr, is 55MB.
  • ebooks: Amazon’s estimates for the Kindle’s storage capacity use an average figure of a little under 900KB per ebook.
  • Podcasts: an hour-long podcast might be about 50MB.
  • Ringtones: a 15-second, good-quality ringtone might take up about 700KB, but you could trim that down with a lower bitrate.

Is it fair that an iPhone or iPad's true storage capacity is less than its advertised capacity?

The methods used when calculating and advertising device capacities might seem unfair - indeed, it would be a more honest assessment for companies to advertise the available storage - but it's the way things are for the time being. Most do acknowledge this discrepancy, of course, but usually in the small print. Apple's phrasing is "actual formatted capacity less", and explains the situation quite comprehensively with this post. Amazon fairly openly says that only 1.25GB of the Kindle's 2GB of storage is available for 'user content'.

Which? ran a test and found that Apple's smartphones are actually among the most frugal in using up storage with initial installs, although you may find it harder to prune iOS than you would with other systems.

Note that a separate issue arises when a large amount of storage is allocated to something called 'Other' when you connect a device to iTunes - perhaps as much as 20GB or more! This is not normal, and is an issue that lots of people have faced. Check for one of the suggested fixes online. Here's some discussion of what consitutes 'Other', and here's discussion on dealing with corrupt Other data.