Padding box-sizing

Padding and Element Width

The CSS width property specifies the width of the element's content area. The content area is the portion inside the padding, border, and margin of an element (the box model).

So, if an element has a specified width, the padding added to that element will be added to the total width of the element. This is often an undesirable result.

Example

  div {
  width: 300px;
  padding: 25px;
}

Padding and box-sizing

The box-sizing property defines how the width and height of an element are calculated: should they include padding and borders, or not.

The box-sizing property can have the following values:

• content-box - This is default. The width and height properties includes only the content (border and padding are not included)
• border-box - The width and height properties includes content, padding and border

So, to keep the width at 300px, no matter the amount of padding, you can use the box-sizing: border-box;. This causes the element to maintain its actual width; if you increase the padding, the available content space will decrease.

Example

  div {
  width: 300px;
  padding: 25px;
  box-sizing: border-box;
}

All CSS Padding Properties