How to Calculate the Uilabel Height Dynamically

How to calculate UILabel height dynamically?

Try this

// UILabel *myLabel;

CGSize labelSize = [myLabel.text sizeWithFont:myLabel.font 
                            constrainedToSize:myLabel.frame.size 
                                lineBreakMode:NSLineBreakByWordWrapping];

CGFloat labelHeight = labelSize.height;

int lines = [myLabel.text sizeWithFont:myLabel.font 
                     constrainedToSize:myLabel.frame.size 
                         lineBreakMode:NSLineBreakByWordWrapping].height/16; 
             // '16' is font size

or

int lines = labelHeight/16;

NSLog(@"lines count : %i \n\n",lines);  

or

int lines = [myLabel.text sizeWithFont:myLabel.font 
                     constrainedToSize:myLabel.frame.size 
                         lineBreakMode:UILineBreakModeWordWrap].height /myLabel.font.pointSize; //fetching font size from font

By Using Categories, Just Create the category class named as

UILabel+UILabelDynamicHeight.h

UILabel+UILabelDynamicHeight.m

No more tension about the height calculation. Please review the below implementation.

Updates for iOS7 & Above,iOS 7 below : Dynamically calculate the UILabel height

#define SYSTEM_VERSION_EQUAL_TO(v)                  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedSame)
#define SYSTEM_VERSION_GREATER_THAN(v)              ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedDescending)
#define SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(v)  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedAscending)
#define SYSTEM_VERSION_LESS_THAN(v)                 ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedAscending)
#define SYSTEM_VERSION_LESS_THAN_OR_EQUAL_TO(v)     ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedDescending)
#define iOS7_0 @"7.0"

UILabel+UILabelDynamicHeight.h

#import <UIKit/UIKit.h>
@interface UILabel (UILabelDynamicHeight)

#pragma mark - Calculate the size the Multi line Label
/*====================================================================*/

    /* Calculate the size of the Multi line Label */

/*====================================================================*/
/**
 *  Returns the size of the Label
 *
 *  @param aLabel To be used to calculte the height
 *
 *  @return size of the Label
 */
 -(CGSize)sizeOfMultiLineLabel;

@end

UILabel+UILabelDynamicHeight.m

#import "UILabel+UILabelDynamicHeight.h"
@implementation UILabel (UILabelDynamicHeight)

#pragma mark - Calculate the size,bounds,frame of the Multi line Label
/*====================================================================*/

/* Calculate the size,bounds,frame of the Multi line Label */

/*====================================================================*/
/**
 *  Returns the size of the Label
 *
 *  @param aLabel To be used to calculte the height
 *
 *  @return size of the Label
 */
-(CGSize)sizeOfMultiLineLabel{

    //Label text
    NSString *aLabelTextString = [self text];

    //Label font
    UIFont *aLabelFont = [self font];

    //Width of the Label
    CGFloat aLabelSizeWidth = self.frame.size.width;

    if (SYSTEM_VERSION_LESS_THAN(iOS7_0)) {
        //version < 7.0

        return [aLabelTextString sizeWithFont:aLabelFont
                            constrainedToSize:CGSizeMake(aLabelSizeWidth, MAXFLOAT)
                                lineBreakMode:NSLineBreakByWordWrapping];
    }
    else if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(iOS7_0)) {
        //version >= 7.0

        //Return the calculated size of the Label
        return [aLabelTextString boundingRectWithSize:CGSizeMake(aLabelSizeWidth, MAXFLOAT)
                                              options:NSStringDrawingUsesLineFragmentOrigin
                                           attributes:@{
                                                        NSFontAttributeName : aLabelFont
                                                        }
                                              context:nil].size;

    }

    return [self bounds].size;

}
@end

How do I calculate the UILabel height dynamically

Use following method to calculate dynamic UILabel height:

- (CGFloat)getLabelHeight:(UILabel*)label
{
    CGSize constraint = CGSizeMake(label.frame.size.width, CGFLOAT_MAX);
    CGSize size;

    NSStringDrawingContext *context = [[NSStringDrawingContext alloc] init];
    CGSize boundingBox = [label.text boundingRectWithSize:constraint
                                                  options:NSStringDrawingUsesLineFragmentOrigin
                                               attributes:@{NSFontAttributeName:label.font}
                                                  context:context].size;

    size = CGSizeMake(ceil(boundingBox.width), ceil(boundingBox.height));

    return size.height;
}

Adjust UILabel height depending on the text

sizeWithFont constrainedToSize:lineBreakMode: is the method to use. An example of how to use it is below:

//Calculate the expected size based on the font and linebreak mode of your label
// FLT_MAX here simply means no constraint in height
CGSize maximumLabelSize = CGSizeMake(296, FLT_MAX);

CGSize expectedLabelSize = [yourString sizeWithFont:yourLabel.font constrainedToSize:maximumLabelSize lineBreakMode:yourLabel.lineBreakMode];   

//adjust the label the the new height.
CGRect newFrame = yourLabel.frame;
newFrame.size.height = expectedLabelSize.height;
yourLabel.frame = newFrame;

How to get exactly height of UILabel with line space?

You can get the exact height of UILabel with exactly passing the same font size and type and doing some calculations.
Here I used a UILabel with Helvetica font with font size 16.

Objective C

- (CGFloat)requiredHeight:(NSString*)labelText{

    UIFont *font = [UIFont fontWithName:@"Helvetica" size:16.0];
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 200, CGFLOAT_MAX)];
    label.numberOfLines = 0;
    label.lineBreakMode = NSLineBreakByWordWrapping;
    label.font = font;
    label.text = labelText;
    [label sizeToFit];
    return label.frame.size.height;

}

Output

CGFloat size = [self requiredHeight:@"iOS Rocks"];
NSLog(@"%f",size);

size = [self requiredHeight:@"iOS Rocks\n"];
NSLog(@"%f",size);

Console Output

2016-04-10 01:37:46.812 testPro[6093:327503] 18.500000
2016-04-10 01:37:46.814 testPro[6093:327503] 37.000000

Swift 2.2

func requiredHeight(labelText:String) -> CGFloat {

    let font = UIFont(name: "Helvetica", size: 16.0)
    let label:UILabel = UILabel(frame: CGRectMake(0, 0, 200, CGFloat.max))
    label.numberOfLines = 0
    label.lineBreakMode = NSLineBreakMode.ByWordWrapping
    label.font = font
    label.text = labelText
    label.sizeToFit()
    return label.frame.height

}

Edit
Swift 3.0

func requiredHeight(labelText:String) -> CGFloat {

    let font = UIFont(name: "Helvetica", size: 16.0)
    let label:UILabel = UILabel(frame: CGRect(x: 0, y: 0, width: 200, height: .max))
    label.numberOfLines = 0
    label.lineBreakMode = .byWordWrapping
    label.font = font
    label.text = labelText
    label.sizeToFit()
    return label.frame.height

}

Adjust UILabel height to text

I've just put this in a playground and it works for me.

Updated for Swift 4.0

import UIKit

 func heightForView(text:String, font:UIFont, width:CGFloat) -> CGFloat{
    let label:UILabel = UILabel(frame: CGRectMake(0, 0, width, CGFloat.greatestFiniteMagnitude))
    label.numberOfLines = 0
    label.lineBreakMode = NSLineBreakMode.byWordWrapping
    label.font = font
    label.text = text

    label.sizeToFit()
    return label.frame.height
}

let font = UIFont(name: "Helvetica", size: 20.0)

var height = heightForView("This is just a load of text", font: font, width: 100.0)

Swift 3:

func heightForView(text:String, font:UIFont, width:CGFloat) -> CGFloat{
    let label:UILabel = UILabel(frame: CGRect(x: 0, y: 0, width: width, height: CGFloat.greatestFiniteMagnitude))
    label.numberOfLines = 0
    label.lineBreakMode = NSLineBreakMode.byWordWrapping
    label.font = font
    label.text = text
    label.sizeToFit()

    return label.frame.height
}

How to get the height of a UILabel in Swift?

it's simple, just call

label.bounds.size.height

How to get the dynamic height of UIView which contains two or more UILabels vertically?

I think your answer lies in layoutIfNeeded and let me explain why

Consider my storyboard set up to set up a Dynamic height UIView which should set its height automatically based on the UILabels within it, note that I did not set the height anchor and so it gives me constraint errors which you can ignore for now as they will be resolved once we are done setting up.

Next I add two labels to this view which have numberOfLines = 0

Top Label constraints

Bottom Label constraints

After this, the constraint errors go away and notice the height of the view in which the labels are contained in is 82:

Now I add this code which dynamically changes the text in the label

class DynamicHeightVC: UIViewController
{
    @IBOutlet var myView: UIView!
    @IBOutlet weak var labelOne: UILabel!
    @IBOutlet weak var labelTwo: UILabel!
    
    var longText = """
    Some really long text that should make the UI label
    expand beyond a few lines and make the UIView expand
    along with it.
    """
    
    var reallyLongText = """
    Some really long text that should make the UI label
    expand beyond a few lines and make the UIView expand
    along with it. Some really long text that should make
    the UI label expand beyond a few lines and make the
    UIView expand along with it.
    """
    
    override func viewDidLoad()
    {
        super.viewDidLoad()
        
        labelOne.text = longText
        labelTwo.text = reallyLongText
        
        print("View height \(myView.frame.height)")
    }
}

The output is View height 82.0 which is the value we saw on the storyboard and it is clearly wrong as the view's height is bigger:

So the issue is once you change / update the text, the constraints get updated and the frames will get updated at a later / different iteration of the main run loop which might not be useful to you since you want to do some calculations with it now.

If you want the frames to be updated in the next turn of the update cycle within the main run loop, you need to call view.setNeedsLayout().

If you want the frames to be updated immediately, you need to call view.layoutIfNeeded()

After making this change, the code is as follows:

class DynamicHeightVC: UIViewController
{
    @IBOutlet var myView: UIView!
    @IBOutlet weak var labelOne: UILabel!
    @IBOutlet weak var labelTwo: UILabel!
    
    var longText = """
    Some really long text that should make the UI label
    expand beyond a few lines and make the UIView expand
    along with it.
    """
    
    var reallyLongText = """
    Some really long text that should make the UI label
    expand beyond a few lines and make the UIView expand
    along with it. Some really long text that should make
    the UI label expand beyond a few lines and make the
    UIView expand along with it.
    """
    
    override func viewDidLoad()
    {
        super.viewDidLoad()
        
        labelOne.text = longText
        labelTwo.text = reallyLongText
        
        view.layoutIfNeeded()
        
        print("Label 1 height \(labelOne.frame.height)")
        print("Label 2 height \(labelTwo.frame.height)")
        print("View height \(myView.frame.height)")
    }
}

And now the console displays the correct, updated height:

Label 1 height 101.5
Label 2 height 183.0
View height 284.5

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