CSS: Round Corners

By Xah Lee. Date: . Last updated: .

border-radius Property

Use border-radius to create round corners.

border-radius is a shorthand for the following properties:

Round corners
.xround-yrncf {
 width: 100px;
 height: 100px;
 border: solid 3px grey;
 border-radius: 10px;
 padding: 8px;
}

Example

Example. Circle

use 50% to make it circle, for any square size.

Different Radius for Each Corner

Border radius can be specified for some corners only. The order is:

border-radius: topLeft topRight bottomRight bottomLeft

Omitting border-radius Values

Any of the 4 values of border-radius values can be omitted.

2 Values (topLeft bottomRight, topRight bottomLeft)

border-radius: x y

is same as

border-radius: x y x y

3 Values (topLeft, topRight bottomLeft, bottomRight)

border-radius: x y z

is the same as

border-radius: x y z y

Example. Left Bracket for Quote

something in the water, does not compute

from a song lyrics by Prince.

.quote-bracket-234 {
 all: revert;
 border-left: solid 2px red;
 border-top-left-radius: 8px;
 border-bottom-left-radius: 8px;
 padding-left: 8px;
 margin-left: 16px;
}

Border Radius with Elliptical Corner

each border radius value can be a fraction, like this:

border-radius:50px/10px 0 0 0

The 50px specifies the horizontal radius of a Ellipse, the 10px is the vertical radius.

css border-radius ellipse illustration
border-radius:55pt/25pt (image source http://www.w3.org/TR/css3-background/#the-border-radius)

Example

50px/10px
.br-frac-448 {
 border: solid 3px grey;
 border-radius: 50px/10px;
 width: 100px;
 height: 100px;
 margin: 10px;
}

50px/10px 0 0 0
.br-frac-174 {
 border: solid 3px grey;
 border-radius: 50px/10px 0 0 0;
 width: 100px;
 height: 100px;
 margin: 10px;
}

Browser Support

All major browsers support it since 2012.

CSS. border, margin, box model