CSS border-radius Property

Example

Add rounded corners to two <div> elements:

#example1 {
  border: 2px solid blue;
  border-radius: 25px;
}

#example2 {
  border: 2px solid blue;
  border-radius: 50px 20px;
}

Definition and Usage

The border-radius property defines the radius of the element's corners.

Tip: This property allows you to add rounded corners to elements! 

This property can have from one to four values. Here are the rules:

Four values - border-radius: 15px 50px 30px 5px; (first value applies to top-left corner, second value applies to top-right corner, third value applies to bottom-right corner, and fourth value applies to bottom-left corner):

 

Three values - border-radius: 15px 50px 30px; (first value applies to top-left corner, second value applies to top-right and bottom-left corners, and third value applies to bottom-right corner):

 

Two values - border-radius: 15px 50px; (first value applies to top-left and bottom-right corners, and the second value applies to top-right and bottom-left corners):

 

One value - border-radius: 15px; (the value applies to all four corners, which are rounded equally:

 

Default value:	0
Inherited:	no
Animatable:	yes.
Version:	CSS3
JavaScript syntax:	object.style.borderRadius="25px"

• Inherited : "Inherited = no" means that it cannot takes (inherit) it's value from it's parent element.
• object - object in javascript means the element on which border-radius is applied.
• Animatable - "Animatable = yes" means that it can be animated with CSS @keyframes.

Browser Support

The numbers in the table specify the first browser version that fully supports the property.

Numbers followed by -webkit- or -moz- specify the first version that worked with a prefix.

Property
border-radius	5.0 4.0 -webkit-	9.0	4.0 3.0 -moz-	5.0 3.1 -webkit-	10.5

CSS Syntax

border-radius: 1-4 length|% / 1-4 length|%|initial|inherit;

Note: The four values for each radius are given in the order top-left, top-right, bottom-right, bottom-left. (15px 20px 10px 5px)

• If bottom-left is omitted it is the same as top-right. (15px 20px 10px is same as 15px 20px 10px 20px)
• If bottom-right is omitted it is the same as top-left. (15px 20px is same as 15px 20px 15px 20px)
• If top-right is omitted it is the same as top-left. (15px is same as 15px 15px 15px 15px)

Property Values

Value	Description	Demo
length	Defines the shape of the corners. Default value is 0.
%	Defines the shape of the corners in %
initial	Sets this property to its default value.
inherit	Inherits this property from its parent element.

More Examples

Example

Set rounded corners for an element with a background color:

#rcorners1 {
  border-radius: 25px;
  background: #0054ff;
  color: #fff;
  padding: 20px;
  width: 200px;
  height: 150px;
}

Example

Set rounded corners for an element with a border:

#rcorners2 {
  border-radius: 25px;
  border: 2px solid #0054ff;
  padding: 20px;
  width: 200px;
  height: 150px;
}

Example

Set rounded corners for an element with a background image: 

#rcorners3 {
  border-radius: 25px;
  background: url(road.jpg);
  background-position: left top;
  background-repeat: repeat;
  padding: 20px;
  width: 200px;
  height: 150px;
}

Example

Also notice this: (Elliptical Border Radius)

e.g. For border-radius: 2em 1em 4em / 0.5em 3em;

The three values before the "/" will be:

• border-top-left-radius = 2em.
• border-top-right-radius = 1em.
• border-bottom-right-radius = 4em.
• border-bottom-left-radius = 1em.

The three values after the "/" will be:

• border-top-left-radius = 0.5em.
• border-top-right-radius = 3em.
• border-bottom-right-radius = 0.5em.
• border-bottom-left-radius = 3em.

These both values respectively combines to create a elliptical border radius :

• border-top-left-radius = 2em 0.5em.
• border-top-right-radius = 1em 3em.
• border-bottom-right-radius = 4em 0.5em.
• border-bottom-left-radius = 1em 3em.

#example1 {
  border-radius: 2em / 5em;
}
/* is equivalent to:
border-top-left-radius: 2em 5em;
border-top-right-radius: 2em 5em;
border-bottom-right-radius: 2em 5em;
border-bottom-left-radius: 2em 5em; */

#example2 {
  border-radius: 2em 1em 4em / 0.5em 3em;
}
/* is equivalent to:
border-top-left-radius: 2em 0.5em;
border-top-right-radius: 1em 3em;
border-bottom-right-radius: 4em 0.5em;
border-bottom-left-radius: 1em 3em; */