ui screen sizes
October 16, 2014

Larger screen size iOS design implications

Written By Sam Jones

Traditionally, user interface design (UI) for iOS devices has been straightforward. Since the inception of the iPhone, mobile designers and mobile developers have had a 3.5 inch screen to work with. Even with the launch of the iPhone 5 and it’s 4 inch screen, mobile designers could easily adapt to the change. This was because the user experience (UX) was fundamentally the same; the user’s fingers and thumb could still reach all corners of the device when holding it with one hand.

However, now that the iPhone 6 and the iPhone 6 Plus are on the market, the size of these devices are starting to make iOS designers go back to the drawing board with their UI and UX ideas. Designs must now take into account the sweeping arc of the thumb. Whilst this is not a new design consideration, it is now much more relevant to iOS designers with the new 4.7 and 5.5-inch devices.

The sweeping arc of the thumb is a term mobile developers and mobile designers use to describe the area of the screen the thumb is most comfortable reaching. As our thumbs remain the same size, the only factor that can change the comfort zone is the size of the device. On 3.5-inch devices such as the iPhone 4 and 4S, the comfort zone is quite large, but the design of the iPhone 6 Plus significantly decreases the thumb’s reach, having important implications on the user interface design.


Commonly, an application with a left menu will have the ubiquitous burger icon in the top-left corner of the screen. As depicted in the image above, this area is not the best place for the icon because users have to stretch their thumbs. This means that mobile designers must come up with new UIs in order to maximize the usability of the content on the screen, whilst bearing in mind ease of navigation.

Mobile designers working with the Android platform have to account for the same user interface design issues too. There has always been a large range of devices that support Android; varying from very small ‘miniature’ phones, through to ‘Phablets’ (large phones) and Tablet devices.

As a result, single view applications are becoming more common. These are one page interfaces/websites that remove the need for navigation buttons. Gestures can be used to swipe from screen to screen if necessary but the focus is, as ever, ease of use.