How to Run iPhone Apps on iPad (and Why You'd Want To)

[Note: for the sake of simplicity, all references to iPhone also refer to iPod touch.]

There are many excellent iOS apps available for download from the App Store that were specifically developed for the iPhone-size screen. With very few exceptions, these apps work perfectly fine on an iPad, and are just as useful. After all, it’s the same iOS that runs on both platforms.

The problem is that many iOS device owners are not necessarily aware of these differences. The result is that iPad owners are likely to miss an opportunity to discover everything they can do with their device. 

The App Store seen from an iPad

By default, when accessing the App Store from an iPad, you are only shown apps available for iPad

One reason for this is that, by default, when you access the App Store from your iPad, you are only shown apps available for iPad. More often than not, this results in iPad owners missing out on the functionality that an “iPhone-only” app would provide even on the larger device. 

In reality, you can indeed locate, purchase, download, install and use the vast majority of apps developed specifically for the smaller iPhone screen.  However, directly from an iPad, the way to do this may be a bit elusive. 

For example, as of this writing, the PayPal app is only available in the smaller iPhone format. By default, if you search for PayPal in the App Store directly from your iPad, you will not find any PayPal app. However, there is a way to search for the iPhone-only version, which is functional on iPad.

The App Store seen from an iPad

With “iPhone Only” selected in the App Store, you can view and download apps onto your iPad

The secret is in the drop-down menu labeled “iPad Only” located at the top of the page. Tap on it and select “iPhone Only” from the drop-down menu. The iPhone version of the PayPal app then appears as accessible, after which you can download, install and use it on your iPad. A similar mechanism is available by accessing the App Store via the Mac iTunes application.

It’s not too late to mention that all this is not much of an issue now that the iPad recently celebrated its fourth birthday. By now, many, if not most of active iOS app developers are creating so-called Universal Apps that contain the code (a.k.a. “binaries”) compiled to run natively on both iPhone and iPad.

Given the utility and ubiquity of the iPad platform, it certainly would be bad-for-business if a decision were made by a developer not to accommodate the larger device. For whatever reason though, some apps – ahem… PayPal – are still living in the iPhone-only world. Nevertheless, you may find that you need – and can certainly utilize – the functionality provided by many apps specifically made for the iPhone. 

Next: Why Would You Want to Run iPhone Apps on Your iPad?

Part 2 - Why Would You Want to Run iPhone Apps on Your iPad?

Why would you want to bother with iPhone-sized apps anyway? The reality is that there are apps that you either MUST run for whatever reason (like some banking or health-related apps), or apps that are truly compelling and useful to you but not yet natively available (or at all) for the iPad. 

By way of example, here’s a list of apps designed for iPhone that I think highly enough to be willing to use them on my iPad:

  • PayPal
  • License Keeper
  • Heard
  • Nag
  • HeyTell
  • iMilk (look, it's not for me; it's for some kids I know!)
  • Flickr
  • inStatus
  • Postagram

In general, as I shop on the App Store, I’m inclined not to consider iPhone-only apps, but there are those few that, for the reasons stated above, I can’t live without on my iPad… as well as on my iPhone, by the way.

So, here’s what actually happens when running iPhone-only apps on iPad… Let’s consider the current iDevice models at the time of this writing – the iPhone 5s and the iPad Air. The iPhone’s screen resolution is 1136 x 640 pixels. For the iPad Air, it’s 2048 x 1536 pixels.

iPhone-only apps can be run on an iPad in either of two zoom modes: the 1X mode or the 2X mode. These modes are indicated within a small circle in the lower-right corner of the iPad screen as the app is running. 

Two iPad screens running an app in normal iPhone resolution and zoomed in

Tap the zoom button on the lower-right corner of the iPad to zoom in and make the iPhone app full screen

In it’s normal mode, the app appears at the same screen resolution it was designed to display as on the iPhone. Because the iPad displays a resolution of about twice that of the iPhone, this results in a smaller view of the app relative to the iPad screen – about half the size. Tap the 2X button to zoom in, where the app’s screen size, in pixels, approximately doubles in order to accommodate it almost full-screen on the iPad. Doing so makes the app easier to use. Tap the 1X button to return the app to its original size.

As is usually the case with this kind of accommodation, there is a tradeoff. The app running in the pixel-doubled 2X mode is obviously of lower quality in terms of sharpness. Everything – text, graphics, keyboards, content – appears larger in 2X mode. However, the app’s functionality – that is, whatever the app is supposed to accomplish for you – is still there. Assuming the app is compatible with the version of iOS that is running on your iPad, it just works. It’s as useful to you as when running it on an iPhone.

For instance, aside from the functionality I get from a couple of iPhone-only photo greeting card apps, I don’t use photo editing apps that are not universal or iPad-native. When working on images, I want the best resolution possible. End of story. Incidentally, the same goes for games.

Next: Perusing the App Store and Some Tips

Part 3 - Perusing the App Store and Some Tips

At this point, you may be wondering how all this applies when actually perusing the App store. Apps in the Store are identified as being either Universal (indicated by a ‘+’ designation) or made to run on a specific device type. The specifications that accompany the app descriptions are fairly clear. 

An icon representing an app on the App Store

App descriptions in the App Store will identify a Universal app with a ‘+’ sign along with further compatibility details

Additionally, some apps strictly made to run natively on an iPad are identified with an “HD” or “for iPad” tagged onto the app’s name. Examples include FX Photo Studio HD and OmniFocus for iPad.

While Universal apps are increasingly common, you are likely to continue to find that some app developers create separate versions of their apps to specifically accommodate the two resolutions. It seems that this is generally done for some of the more complex, higher-end apps. You may be required to purchase each individually if you want a copy for each device. Again, the FX Photo Studio and OmniFocus apps come to mind.

Finally, here are a few tips when using apps designed for iPhone on your iPad:

  • Apps may only work in portrait or landscape orientation. These apps will change orientation even with screen rotation lock enabled.
  • Text and graphics may not appear as sharp when using 2X mode. If you prefer sharper text and graphics, use 1X instead.
  • Some features may not be available on iPad (for example, apps that let you make phone calls or use the iPhone camera to take pictures on an older camera-less iPad).

To sum things up, we’ve learned that:

  • Universal apps work on all devices.
  • iPad-specific apps will not work on iPhone.
  • Assuming the apps in question are compatible with the installed version of iOS, most iPhone-only apps will work on iPad, albeit in pixel-doubled mode.

Don’t let the fact that an app was specifically designed for the smaller iPhone screen discourage you from fully enjoying its intended functionality right there on your iPad.