[ios] How do I change the font size of a UILabel in Swift?

label.font.pointSize is read-only, so I'm not sure how to change it.

We can set font as per our requirement like,

label.font = UIFont(name: "Avenir-Light", size: 15.0)
label.font = UIFont.boldSystemFontOfSize(15)
label.font = UIFont.italicSystemFontOfSize(15)
label.font = UIFont.systemFontOfSize(17)

Swift-3.1

label.font = UIFont.systemFont(ofSize: 12)

Swift 4.2

myLabel.font = UIFont.systemFont(ofSize: 12)

In case you want to use custom font with bold option:

nameLabel.font = UIFont(name: "GillSans-Bold", size: 27)

swift 4:

label.font = UIFont("your font name", size: 15)

also if you want to set the label font in all views in your project try this in appDelegate>didFinishLaunch: UILabel.appearance().font = UIFont("your font name", size: 15)

Apple keep changing things for no reason: Swift 4+:

myLabel.font = UIFont.systemFont(ofSize: 16)

thanks apple for wasting people time to figure out what "font size" methods they need to use!

In Swift 3 again...

myLabel.font = myLabel.font.withSize(18)

You can use an extension.

import UIKit

extension UILabel {

    func sizeFont(_ size: CGFloat) {
        self.font = self.font.withSize(size)
    }
}

To use it:

self.myLabel.fontSize(100)

In Swift 3:

label = UIFont.systemFont(ofSize: 20)

and to use system preset sizes, for example:

label = UIFont.systemFont(ofSize: UIFont.smallSystemFontSize)

Programmatically

label.font = UIFont.systemFont(ofSize: 20.0)
label.font = UIFont.boldSystemFont(ofSize: 20.0)
label.font = UIFont.italicSystemFont(ofSize: 20.0)

label.font = UIFont(name:"Helvetica Neue", size: 20.0)//Set your font name here

Through Story board

To display multiple lines set 0(Zero), this will display more than one line in your label.

If you want to display only 2 lines set 2.

If you want to set minimum font size for label Click Autoshrink and Select Minimum Font Size option

See below screens

Here set minimum font size

EX: 9 (In this image)

If your label get more text at that time your label text will be shrink upto 9

SWIFT 3.1

Label.font = Label.font.withSize(NewValue)

You can give like this also

labelName.font = UIFont(name: "systemFont", size: 30)

Swift 3

label.font.withSize(16)

I used fontWithSize for a label with light system font, but it changes back to normal system font.

If you want to keep the font's traits, better to include the descriptors.

label.font = UIFont(descriptor: label.font.fontDescriptor(), size: 16.0)

If you want just change size of your font i create this extension

// Add extension

extension UILabel {
    func setSizeFont (sizeFont: Double) {
        self.font =  UIFont(name: self.font.fontName, size: sizeFont)!
        self.sizeToFit()
    }
}

// Use

myLabel.setSizeFont(60)

It's very easy and convenient to change font size from storyboard, and you can instantly see the result of the change.

Actually, it's also very easy to change other font attributes on storyboard too, like style, font family, etc.

Swift 3.1

import UIKit

extension UILabel {
    var fontSize: CGFloat {
        get {
            return self.font.pointSize
        }
        set {
            self.font =  UIFont(name: self.font.fontName, size: newValue)!
            self.sizeToFit()
        }
    }
}

In swift3, suppose your UILable name is myLable and you want to change its font size do this

myLable.font = UIFont.systemFont(ofSize: 10)

label.font = UIFont.systemFontOfSize(20)

I think the best way to do this - if keeping the same font that is already assigned to the UILabel would be:

(using Swift)

label.font = label.font.fontWithSize(20)

(using Swift 3)

label.font = label.font.withSize(20)

Ideally I would set this in the viewDidLayoutSubviews method, as it doesn't need to change every time the view appears.