box-sizing:border-box

box-sizing:border-box is a CSS property that changes the way the browser calculates the size of an element. When you set the box-sizing property to border-box

the element's padding and border are included in the element's total width and height.

This property is extremely useful when working with layout and design

as it helps ensure that the sizing of elements is consistent and predictable. By default

when you set the width or height of an element in CSS

you are setting the size of the content area of the element. This means that any padding or borders that you add to the element will be added on top of the specified width or height. This can lead to unexpected results and make it difficult to create layouts that look the way you intended.

By setting the box-sizing property to border-box

you are telling the browser to calculate the width and height of the element including the padding and border. This means that the content area of the element will be adjusted to accommodate the padding and border

ensuring that the total width and height of the element remains consistent regardless of any additional padding or border.

One common example of when box-sizing:border-box is useful is when creating a grid layout with evenly spaced columns. By setting all of the columns to have a width of 25% and using box-sizing:border-box

you can ensure that each column will be the same width and have the same spacing between them

even when adding padding or borders to the columns.

Another benefit of using box-sizing:border-box is that it can help simplify your CSS code. Instead of having to manually adjust the width or height of an element to account for padding or borders

you can simply set the box-sizing property to border-box and let the browser handle the calculations for you.

In conclusion

box-sizing:border-box is a powerful CSS property that can help make your web design and layout work easier and more consistent. By using this property

you can ensure that the sizing of your elements remains predictable and that your layouts look the way you intended. It is a simple yet effective tool that can save you time and frustration when working with CSS.