borderRadius property

Specifies the radii of a quarter ellipse that defines the shape of the corners for the outer border edge of the current box.


Integer value = object.put_borderRadius(BSTR v);Integer value = object.get_borderRadius(BSTR* sRadius);

Property values

Type: BSTR

One to eight of either of the following values, separated by an optional slash ("/"):

length (length)

Floating-point number, followed by a supported length unit.

percentage (percentage)

An integer, followed by a %. The value is a percentage of, for horizontal radii, the width of the border box, or for vertical radii, the height of the border box.

String format

[ <length> | <percentage> ] {1,4} [ / [ <length> | <percentage> ] {1,4} ] ?

CSS information

Applies To All elements
Media visual
Inherited no
Initial Value (see individual properties)

Standards information


The IHTMLCSSStyleDeclaration::borderRadius property is a composite property that specifies up to four border-*-radius properties. If values are given before and after the slash, the values before the slash set the horizontal radius and the values after the slash set the vertical radius. If there is no slash, the values set both radii equally.

The four values for each radius are given in the following order:

If the bottom-left value is omitted, the value is the same as the top-right value. If the bottom-right value is omitted, the value is the same as the top-left value. If the top-right value is omitted, the value is the same as the top-left value.

For more information about the IHTMLCSSStyleDeclaration::borderRadius property and related properties, see How to Add Rounded Corners with CSS3.


Following is an example of a typical use for the IHTMLCSSStyleDeclaration::borderRadius property. Because there are two values after the IHTMLCSSStyleDeclaration::borderRadius property, the first value is the radius of the circle that defines the top-left and bottom-right corners of the element, and the second value is the radius of the circle that defines the top-right and bottom-left corners of the element.

div.rounded {
  width: 800px;
  height: 600px;
  border: solid black 10px;
  border-radius: 15px 10px 

This example appears as follows in Internet Explorer 9 and later.

The following two selectors are equivalent; they produce identical results.

div.shorthand {
  border-radius: 40px;

div.all4properties {
  border-top-left-radius: 40px;
  border-top-right-radius: 40px; 
  border-bottom-right-radius: 40px;
  border-bottom-left-radius: 40px;

The following two selectors are also equivalent.

div.shorthand2 {
  border-radius: 2em 1em 4em / 0.5em 3em;

div.all4properties2 {
  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;


Minimum supported client

Windows Vista with SP1, Windows 7

Minimum supported server

Windows Server 2008 R2







See also


IE Test Drive: Border Radius

IE Test Drive: IE Logo


How to Add Rounded Corners with CSS3

Internet Explorer 9 Guide for Developers: CSS3 Backgrounds and Borders Module