CSS Box Sizing: How to use?

CSS Box Sizing is a property that allows you to specify how the total width and height of an HTML element are calculated. By default, when you set the width and height of an element, those dimensions only apply to the content inside the element. The padding, border, and margin are added to the dimensions of the element, making it larger than you might expect. However, by using the CSS Box Sizing property, you can change this behavior and make the dimensions of an element include its padding and border.

In this tutorial, we’ll cover how to use CSS Box Sizing to adjust the sizing of your HTML elements.

Syntax

The syntax for the CSS Box Sizing property is simple:

box-sizing: content-box | border-box;

• content-box is the default value. When this value is used, the size of an element is calculated based on the width and height of its content, and any padding, border, or margin are added to the outside of the element.
• border-box is the value that includes the padding and border in the total size of an element. When this value is used, the width and height of an element include its padding and border.

How to Use CSS Box Sizing

Using CSS Box Sizing is easy. You can set it on any element you want by using the box-sizing property in your CSS code.

Step 1: Choose the Element

First, you’ll need to choose the element that you want to apply the CSS Box Sizing property to. You can select an element by using its tag name, class, or ID in your CSS code.

For example, let’s say you have an HTML element with the class name box. You can select this element in your CSS code by using the following code:

.box {
  /* CSS code goes here */
}

Step 2: Set the Box Sizing Property

Next, you’ll need to set the box-sizing property to either content-box or border-box, depending on how you want the element to be sized.

For example, if you want the element with the box class to include its padding and border in its total size, you can use the following code:

.box {
  box-sizing: border-box;
}

Step 3: Set the Width and Height

Finally, you’ll need to set the width and height properties of the element. When you use the border-box value for box-sizing, the width and height properties will include the padding and border.

For example, if you want the element with the box class to have a width of 200 pixels and a height of 100 pixels, you can use the following code:

.box {
  box-sizing: border-box;
  width: 200px;
  height: 100px;
}

Conclusion

CSS Box Sizing is a simple but powerful property that allows you to control how the width and height of your HTML elements are calculated. By using the border-box value for box-sizing, you can include the padding and border in the total size of an element, making it easier to create layouts that behave the way you want.