08. Box Sizing

The default selection for a CSS box is just the box's content, without the padding and border. Consequently, if you define the height and width, it'll only pertain to the box's content area.

If you'd like to specify that the content includes the padding and border, we use the box-sizing property with a border-box value. The default value is content-box.

#box1, #box2 {
  border: 1px solid black;
  border-radius: 10px;
  text-align: center;
  padding: 10px;
  height: 50%;
  width: 50%;
  margin: 10px auto;
}
  
#box1 {
  box-sizing: content-box;
}
  
#box2 {
  box-sizing: border-box;
} 
This is box 1.
This is box 2.

Notice how the first box is bigger, since the height applied only applies to the content area.

Build modern and responsive webpages

High Performance Web Sites

Build modern and responsive webpages Try Front-end

Want your web site to display more quickly? This book presents 14 specific rules that will cut 25% to 50% off response time when users request a page. Author Steve Souders, in his job as Chief Performance Yahoo!, collected these best practices while optimizing some of the most-visited pages on the Web.

$ Check price
29.9929.99Amazon 4.5 logo(63+ reviews)

More Front-end resources

Aching back from coding all day?

Foam Seat Cushion

Aching back from coding all day? Try Back Problems

This foam seat cushion relieves lowerback pain, numbness and pressure sores by promoting healthy weight distribution, posture and spine alignment. Furthermore, it reduces pressure on the tailbone and hip bones while sitting. Perfect for sitting on the computer desk for long periods of time.

$ Check price
99.9599.95Amazon 4.5 logo(9,445+ reviews)

More Back Problems resources

Ad