How to detect iPhone 5 (widescreen devices)?

First of all, you shouldn't rebuild all your views to fit a new screen, nor use different views for different screen sizes.

Use the auto-resizing capabilities of iOS, so your views can adjust, and adapt any screen size.

That's not very hard, read some documentation about that. It will save you a lot of time.

iOS 6 also offers new features about this.
Be sure to read the iOS 6 API changelog on Apple Developer website.
And check the new iOS 6 AutoLayout capabilities.

That said, if you really need to detect the iPhone 5, you can simply rely on the screen size.

[ [ UIScreen mainScreen ] bounds ].size.height

The iPhone 5's screen has a height of 568.
You can imagine a macro, to simplify all of this:

#define IS_IPHONE_5 ( fabs( ( double )[ [ UIScreen mainScreen ] bounds ].size.height - ( double )568 ) < DBL_EPSILON )

The use of fabs with the epsilon is here to prevent precision errors, when comparing floating points, as pointed in the comments by H2CO3.

So from now on you can use it in standard if/else statements:

if( IS_IPHONE_5 ){}else{}

Edit - Better detection

As stated by some people, this does only detect a widescreen, not an actual iPhone 5.

Next versions of the iPod touch will maybe also have such a screen, so we may use another set of macros.

Let's rename the original macro IS_WIDESCREEN:

#define IS_WIDESCREEN ( fabs( ( double )[ [ UIScreen mainScreen ] bounds ].size.height - ( double )568 ) < DBL_EPSILON )

And let's add model detection macros:

#define IS_IPHONE ( [ [ [ UIDevice currentDevice ] model ] isEqualToString: @"iPhone" ] )#define IS_IPOD   ( [ [ [ UIDevice currentDevice ] model ] isEqualToString: @"iPod touch" ] )

This way, we can ensure we have an iPhone model AND a widescreen, and we can redefine the IS_IPHONE_5 macro:

#define IS_IPHONE_5 ( IS_IPHONE && IS_WIDESCREEN )

Also note that, as stated by @LearnCocos2D, this macros won't work if the application is not optimised for the iPhone 5 screen (missing the Default-568h@2x.png image), as the screen size will still be 320x480 in such a case.

I don't think this may be an issue, as I don't see why we would want to detect an iPhone 5 in a non-optimized app.

IMPORTANT - iOS 8 support

On iOS 8, the bounds property of the UIScreen class now reflects the device orientation.
So obviously, the previous code won't work out of the box.

In order to fix this, you can simply use the new nativeBounds property, instead of bounds, as it won't change with the orientation, and as it's based on a portrait-up mode.
Note that dimensions of nativeBounds is measured in pixels, so for an iPhone 5 the height will be 1136 instead of 568.

If you're also targeting iOS 7 or lower, be sure to use feature detection, as calling nativeBounds prior to iOS 8 will crash your app:

if( [ [ UIScreen mainScreen ] respondsToSelector: @selector( nativeBounds ) ] ){    /* Detect using nativeBounds - iOS 8 and greater */}else{    /* Detect using bounds - iOS 7 and lower */}

You can adapt the previous macros the following way:

#define IS_WIDESCREEN_IOS7 ( fabs( ( double )[ [ UIScreen mainScreen ] bounds ].size.height - ( double )568 ) < DBL_EPSILON )#define IS_WIDESCREEN_IOS8 ( fabs( ( double )[ [ UIScreen mainScreen ] nativeBounds ].size.height - ( double )1136 ) < DBL_EPSILON )#define IS_WIDESCREEN      ( ( [ [ UIScreen mainScreen ] respondsToSelector: @selector( nativeBounds ) ] ) ? IS_WIDESCREEN_IOS8 : IS_WIDESCREEN_IOS7 )

And obviously, if you need to detect an iPhone 6 or 6 Plus, use the corresponding screen sizes.

Tested and designed for any combination of SDK and OS:

Swift

Added iPad types. iPad 2 and iPad mini are non-retina iPads. While iPad Mini 2 & above, iPad 3, 4, iPad Air, Air 2, Air 3, and iPad Pro 9.7 have same logical resolution of 1024. iPad Pro has maxLength of 1366. Reference

import UIKitpublic enum DisplayType {    case unknown    case iphone4    case iphone5    case iphone6    case iphone6plus    case iPadNonRetina    case iPad    case iPadProBig    static let iphone7 = iphone6    static let iphone7plus = iphone6plus}public final class Display {    class var width:CGFloat { return UIScreen.main.bounds.size.width }    class var height:CGFloat { return UIScreen.main.bounds.size.height }    class var maxLength:CGFloat { return max(width, height) }    class var minLength:CGFloat { return min(width, height) }    class var zoomed:Bool { return UIScreen.main.nativeScale >= UIScreen.main.scale }    class var retina:Bool { return UIScreen.main.scale >= 2.0 }    class var phone:Bool { return UIDevice.current.userInterfaceIdiom == .phone }    class var pad:Bool { return UIDevice.current.userInterfaceIdiom == .pad }    class var carplay:Bool { return UIDevice.current.userInterfaceIdiom == .carPlay }    class var tv:Bool { return UIDevice.current.userInterfaceIdiom == .tv }    class var typeIsLike:DisplayType {        if phone && maxLength < 568 {            return .iphone4        }        else if phone && maxLength == 568 {                return .iphone5        }        else if phone && maxLength == 667 {            return .iphone6        }        else if phone && maxLength == 736 {            return .iphone6plus        }        else if pad && !retina {            return .iPadNonRetina        }        else if pad && retina && maxLength == 1024 {            return .iPad        }        else if pad && maxLength == 1366 {            return .iPadProBig        }        return .unknown    }}

See it in actionhttps://gist.github.com/hfossli/bc93d924649de881ee2882457f14e346

Note: If e.g. iPhone 6 is in zoomed mode the UI is a zoomed up version of iPhone 5. These functions is not determining device type, but display mode thus iPhone 5 is the desired result in this example.

Objective-C

#define IS_IPAD (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)#define IS_IPHONE (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone)#define IS_RETINA ([[UIScreen mainScreen] scale] >= 2.0)#define SCREEN_WIDTH ([[UIScreen mainScreen] bounds].size.width)#define SCREEN_HEIGHT ([[UIScreen mainScreen] bounds].size.height)#define SCREEN_MAX_LENGTH (MAX(SCREEN_WIDTH, SCREEN_HEIGHT))#define SCREEN_MIN_LENGTH (MIN(SCREEN_WIDTH, SCREEN_HEIGHT))#define IS_ZOOMED (IS_IPHONE && SCREEN_MAX_LENGTH == 736.0)#define IS_IPHONE_4_OR_LESS (IS_IPHONE && SCREEN_MAX_LENGTH < 568.0)#define IS_IPHONE_5 (IS_IPHONE && SCREEN_MAX_LENGTH == 568.0)#define IS_IPHONE_6 (IS_IPHONE && SCREEN_MAX_LENGTH == 667.0)#define IS_IPHONE_6P (IS_IPHONE && SCREEN_MAX_LENGTH == 736.0)

Usage: http://pastie.org/9687735

Note: If e.g. iPhone 6 is in zoomed mode the UI is a zoomed up version of iPhone 5. These functions is not determining device type, but display mode thus iPhone 5 is the desired result in this example.

Really simple solution

if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone){    CGSize result = [[UIScreen mainScreen] bounds].size;    if(result.height == 480)    {        // iPhone Classic    }    if(result.height == 568)    {        // iPhone 5    }}