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
.roundcorners-059 {
 width: 100px;
 height: 100px;
 border: solid 3px grey;
 border-radius: 10px;
 padding: 8px;
}

Example

0px
10px
20px
30px
40px
50px
50px

Different Radius for Each Corner

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

border-radius:topLeft topRight bottomRight bottomLeft

20px 0 0 0
0 20px 0 0
0 0 20px 0
0 0 0 20px

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

20px 0px
.br2vals {
 border-radius: 20px 0px;
}

3 Values (topLeft, topRight bottomLeft, bottomRight)

border-radius:x y z, is the same as border-radius:x y z y

30px 0px 10px
.br3vals {
 border-radius: 30px 0px 10px;
}

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)

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