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border-radius

The border-radius CSS property rounds the corners of an element's outer border edge. You can set a single radius to make circular corners, or two radii to make elliptical corners.

Try it

The radius applies to the whole background, even if the element has no border; the exact position of the clipping is defined by the background-clip property.

The border-radius property does not apply to table elements when border-collapse is collapse.

Note: As with any shorthand property, individual sub-properties cannot inherit, such as in border-radius:0 0 inherit inherit, which would partially override existing definitions. Instead, the individual longhand properties have to be used.

Constituent properties

This property is a shorthand for the following CSS properties:

Syntax

css

/* The syntax of the first radius allows one to four values */
/* Radius is set for all 4 sides */
border-radius: 10px;

/* top-left-and-bottom-right | top-right-and-bottom-left */
border-radius: 10px 5%;

/* top-left | top-right-and-bottom-left | bottom-right */
border-radius: 2px 4px 2px;

/* top-left | top-right | bottom-right | bottom-left */
border-radius: 1px 0 3px 4px;

/* The syntax of the second radius allows one to four values */
/* (first radius values) / radius */
border-radius: 10px / 20px;

/* (first radius values) / top-left-and-bottom-right | top-right-and-bottom-left */
border-radius: 10px 5% / 20px 30px;

/* (first radius values) / top-left | top-right-and-bottom-left | bottom-right */
border-radius: 10px 5px 2em / 20px 25px 30%;

/* (first radius values) / top-left | top-right | bottom-right | bottom-left */
border-radius: 10px 5% / 20px 25em 30px 35em;

/* Global values */
border-radius: inherit;
border-radius: initial;
border-radius: revert;
border-radius: revert-layer;
border-radius: unset;

The border-radius property is specified as:

  • one, two, three, or four <length> or <percentage> values. This is used to set a single radius for the corners.
  • followed optionally by "/" and one, two, three, or four <length> or <percentage> values. This is used to set an additional radius, so you can have elliptical corners.

Values

radius A light blue rectangle with a light gray border. All 4 corners are rounded. Is a <length> or a <percentage> denoting a radius to use for the border in each corner of the border. It is used only in the one-value syntax.
top-left-and-bottom-right A light blue rectangle with a light gray border. The 2 corners on the top left and the bottom right have are rounded. Is a <length> or a <percentage> denoting a radius to use for the border in the top-left and bottom-right corners of the element's box. It is used only in the two-value syntax.
top-right-and-bottom-left A light blue rectangle with a light gray border. The 2 corners on the top right and the bottom left are rounded. Is a <length> or a <percentage> denoting a radius to use for the border in the top-right and bottom-left corners of the element's box. It is used only in the two- and three-value syntaxes.
top-left A light blue rectangle with a light gray border. The corner on the top left is rounded. Is a <length> or a <percentage> denoting a radius to use for the border in the top-left corner of the element's box. It is used only in the three- and four-value syntaxes.
top-right A light blue rectangle with a light gray border. The corner on the top right is rounded. Is a <length> or a <percentage> denoting a radius to use for the border in the top-right corner of the element's box. It is used only in the four-value syntax.
bottom-right A light blue rectangle with a light gray border. The bottom right corner is rounded. Is a <length> or a <percentage> denoting a radius to use for the border in the bottom-right corner of the element's box. It is used only in the three- and four-value syntaxes.
bottom-left A light blue rectangle with a light gray border. The bottom left corner is rounded. Is a <length> or a <percentage> denoting a radius to use for the border in the bottom-left corner of the element's box. It is used only in the four-value syntax.
<length>

Denotes the size of the circle radius, or the semi-major and semi-minor axes of the ellipse, using length values. Negative values are invalid.

<percentage>

Denotes the size of the circle radius, or the semi-major and semi-minor axes of the ellipse, using percentage values. Percentages for the horizontal axis refer to the width of the box; percentages for the vertical axis refer to the height of the box. Negative values are invalid.

For example:

css

border-radius: 1em/5em;

/* It is equivalent to: */
border-top-left-radius: 1em 5em;
border-top-right-radius: 1em 5em;
border-bottom-right-radius: 1em 5em;
border-bottom-left-radius: 1em 5em;

css

border-radius: 4px 3px 6px / 2px 4px;

/* It is equivalent to: */
border-top-left-radius: 4px 2px;
border-top-right-radius: 3px 4px;
border-bottom-right-radius: 6px 2px;
border-bottom-left-radius: 3px 4px;

Formal definition

Initial value as each of the properties of the shorthand:
Applies to all elements; but User Agents are not required to apply to table and inline-table elements when border-collapse is collapse. The behavior on internal table elements is undefined for the moment.. It also applies to ::first-letter.
Inherited no
Percentages refer to the corresponding dimension of the border box
Computed value as each of the properties of the shorthand:
Animation type as each of the properties of the shorthand:

Formal syntax

border-radius = 
  <length-percentage [0,∞]>{1,4} [ / <length-percentage [0,∞]>{1,4} ]?  

<length-percentage> = 
  <length>      |
  <percentage>

Examples

Live Samples

Specifications

Specification
CSS Backgrounds and Borders Module Level 3
# border-radius

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
4_values_for_4_corners 4 12 4 9 10.5 5 ≤37 18 4 11 4.2 1.0
border-radius
4Chrome ignores border-radius on <select> elements unless -webkit-appearance is overridden to an appropriate value.
1		 1212
4["Before Firefox 50, border styles of rounded corners (with border-radius) were always rendered as if border-style was solid. This has been fixed in Firefox 50.", "To conform to the CSS3 standard, Firefox 4 changes the handling of <percentage> values to match the specification. You can specify an ellipse as a border on an arbitrary sized element with border-radius: 50%;. Firefox 4 also makes rounded corners clip content and images if overflow: visible is not set."]
1–12		 9
10.5Before Opera 11.60, replaced elements with border-radius do not have rounded corners.
5Safari ignores border-radius on <select> elements unless -webkit-appearance is overridden to an appropriate value.
3		 ≤372 18
4Before Firefox 50, border styles of rounded corners (with border-radius) were always rendered as if border-style was solid. This has been fixed in Firefox 50.
4–14		 11
4.2Safari ignores border-radius on <select> elements unless -webkit-appearance is overridden to an appropriate value.
1		 1.0
elliptical_borders
1Before Chrome 4, the slash / notation is unsupported. If two values are specified, then an elliptical border is drawn on all four corners. -webkit-border-radius: 40px 10px; is equivalent to border-radius: 40px / 10px;.
12 4 9 10.5
3Before Safari 5, the slash / notation is unsupported. If two values are specified, then an elliptical border is drawn on all four corners. -webkit-border-radius: 40px 10px; is equivalent to border-radius: 40px / 10px;.
≤37 18 4 11 4.2 1.0
percentages 8 12
4Before Firefox 4, <percentage> values are implemented in a non-standard way. Both horizontal and vertical radii were relative to the width of the border box.
9
11.5Before Opera 11.5, the implementation of <percentage> values was buggy.
5.1 ≤37 18 4 11.5 5 1.0

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/CSS/border-radius