CSS Border Radius Generator | css3.com

How to Use the CSS Border Radius Generator

What Is the CSS Border Radius Generator?

The CSS Border Radius Generator is a free online tool that lets you visually customize the rounding of each corner of any HTML element. Border-radius is one of the most commonly used CSS properties in modern web design, transforming sharp rectangular elements into smooth, rounded shapes that feel more natural and visually appealing.

With this tool, you can independently control the radius of each corner - top-left, top-right, bottom-right, and bottom-left - using simple sliders. The live preview shows your shape in real time, and the generated CSS code is ready to copy or download with one click.

How Does It Work?

The tool provides four individual sliders, one for each corner of the element. Each slider controls the border radius value in pixels, ranging from 0 (sharp corner) to 100 pixels (fully rounded). As you adjust each slider, the preview element updates instantly to show the exact shape you're creating.

When all four corners have the same value, the output uses the shorthand border-radius property with a single value. When corners differ, it outputs the full four-value shorthand: top-left, top-right, bottom-right, bottom-left. This makes the generated code clean and optimized for your specific design.

To create a perfect circle, set all four corners to 50% - or use a high pixel value that exceeds half the element's dimension. For pill-shaped buttons, apply a very large radius (like 999px) to create fully rounded ends on rectangular elements.

CSS Border Radius Syntax

/* Equal corners */
border-radius: 25px;

/* Individual corners */
border-radius: 10px 20px 30px 40px;
/* top-left | top-right | bottom-right | bottom-left */

/* Perfect circle */
border-radius: 50%;

/* Pill shape */
border-radius: 999px;

/* Elliptical corners */
border-radius: 50px / 25px;

Common Use Cases

●Buttons and CTAs - rounded corners make buttons feel more clickable and modern compared to sharp rectangles
●Avatar images - use border-radius: 50% to create perfectly circular user profile pictures
●Cards and containers - subtle rounding (4-12px) softens card edges for a polished, modern look
●Input fields - rounded inputs are a hallmark of modern form design, creating a friendly user experience
●Tags and badges - pill-shaped badges (with high border-radius values) are widely used for labels and status indicators
●Decorative shapes - combine asymmetric border-radius values to create organic, blob-like shapes for backgrounds

Advanced Border Radius Techniques

The border-radius property actually supports elliptical corners using the slash syntax. For example, 'border-radius: 50px / 25px' creates corners that are wider horizontally than vertically, resulting in oval-shaped rounding. This is incredibly useful for creating organic, asymmetric shapes that go beyond simple circular corners.

You can also target individual corners independently using the longhand properties: border-top-left-radius, border-top-right-radius, border-bottom-right-radius, and border-bottom-left-radius. Each of these also accepts elliptical values, giving you complete control over every aspect of the corner curve.

For responsive designs, consider using percentage-based values instead of pixels. Percentages are relative to the element's dimensions, so a 20% radius will scale proportionally as the element resizes across different screen sizes. This ensures your rounded corners look consistent on mobile, tablet, and desktop layouts.