iPhone system font

Solution 1:

To the delight of font purists everywhere, the iPhone system interface uses Helvetica or a variant thereof.

The original iPhone, iPhone 3G and iPhone 3GS system interface uses Helvetica. As first noted by the always excellent DaringFireball, the iPhone 4 uses a subtly revised font called "Helvetica Neue." DaringFireball also notes that this change is related to the iPhone 4 display rather than the iOS 4 operating system and older iPhone models running iOS 4 still use Helvetica as the system font.

iPod models released prior to the iPhone use either Chicago, Espy Sans, or Myriad and use Helvetica after the release of the iPhone.

From http://www.everyipod.com/iphone-faq/iphone-who-designed-iphone-font-used-iphone-ringtones.html

For iOS9 it has changed to San Fransisco. See http://developer.apple.com/fonts for more info.

Solution 2:

If you're doing programatic customisation, don't hard code the system font. Use UIFont systemFontOfSize:, UIFont boldSystemFontOfSize: and UIFont italicSystemFontOfSize (Apple documentation).

This has become especially relevant since iOS 7, which changed the system font to Helvetica Neue.

This has become super especially relevant since iOS 9, which changed the system font again to San Francisco.

Solution 3:

afaik iPhone uses "Helvetica" by default < iOS 10

Solution 4:

Swift

Specific font

Setting a specific font in Swift is done like this:

let myFont = UIFont(name: "Helvetica", size: 17)

If you don't know the name, you can get a list of the available font names like this:

print(UIFont.familyNames())

Or an even more detailed list like this:

for familyName in UIFont.familyNames() {
    print(UIFont.fontNamesForFamilyName(familyName))
}

But the system font changes from version to version of iOS. So it would be better to get the system font dynamically.

System font

let myFont = UIFont.systemFontOfSize(17)

But we have the size hard-coded in. What if the user's eyes are bad and they want to make the font larger? Of course, you could make a setting in your app for the user to change the font size, but this would be annoying if the user had to do this separately for every single app on their phone. It would be easier to just make one change in the general settings...

Dynamic font

let myFont = UIFont.preferredFont(forTextStyle: .body)

Ah, now we have the system font at the user's chosen size for the Text Style we are working with. This is the recommended way of setting the font. See Supporting Dynamic Type for more info on this.

Visual List of iOS Fonts
How do I make an attributed string using Swift?