Free CSS Border Radius Generator Online

What is the CSS border radius generator?

The CSS border radius generator is a free online tool that creates the border-radius CSS needed to round the corners of an element. Instead of guessing values and reloading your page, you adjust a visual preview and the tool writes the matching CSS for you.

The border-radius property accepts one to four values for the four corners, plus a slash for elliptical radii, so it can produce anything from a subtle rounded button to a full circle. The generator exposes all of these options through sliders, corner inputs, and presets, then outputs the exact border-radius declaration you can paste into your stylesheet.

How to use the CSS border radius generator?

Generating rounded corners CSS takes only a few seconds, and nothing is uploaded. Follow these steps:

• Set the corner radius: Use the slider or drag the corner handles on the live preview to round the element. The preview updates instantly as you change the radius.
• Edit each corner if needed: Enable Edit corners separately to give the top-left, top-right, bottom-right, and bottom-left corners their own radius values for asymmetric shapes.
• Choose vendor prefixes: Pick WebKit, Gecko, or CSS3 output so the generated border-radius CSS matches the browsers and engines you need to support.
• Copy the CSS: Copy the generated border-radius CSS or download it as a file, then paste it into your stylesheet to apply the rounded corners.

Understanding the border-radius property

Knowing how border-radius reads its values makes the generated CSS easy to tweak by hand. The property is a shorthand that controls all four corners and supports both circular and elliptical rounding. Here is how each part works:

• Shorthand Values: One value rounds all four corners equally, while two, three, or four values target corners in clockwise order starting from the top-left.
• Four Corners: The order is top-left, top-right, bottom-right, then bottom-left, so any corner can carry a different radius for asymmetric shapes.
• Pixels vs Percentage: A pixel radius stays fixed, while a percentage radius scales with the element, and 50 percent on a square box forms a circle.
• Elliptical Radii: A slash splits each radius into horizontal and vertical parts, as in border-radius: 40px / 20px, producing oval corners instead of circular ones.
• Copy-Ready Output: The generator collapses equal corners into a single value and expands uneven corners into the full shorthand, so the CSS stays clean.

Features of the border radius generator

As a tool, the border radius generator offers a few capabilities that make rounding corners effortless. Here are the features of our generator:

• Live Visual Preview: A draggable preview box shows the rounded shape in real time, so you can shape corners by eye instead of guessing values.
• Per-Corner Control: Edit all four corners together or independently, which makes both uniform rounding and asymmetric designs quick to build.
• Handy Presets: One-click Sharp, Subtle, Rounded, Large, and Max presets give you a fast starting point for common button and card styles.
• Vendor Prefix Output: Optional WebKit and Gecko prefixes are added alongside the standard property for broader engine and legacy browser coverage.
• Browser-Based Processing: All rounding and CSS generation runs locally in your browser, so nothing is uploaded and the tool works offline once loaded.
• Copy and Download: Copy the generated CSS to your clipboard or download it as a file, ready to drop straight into a stylesheet.

Use cases of the border radius generator

Rounded corners appear across almost every interface, and the generator speeds up each of these design tasks by writing the CSS for you:

• Buttons and Cards: Dial in consistent corner rounding for buttons, cards, and inputs so your component library shares one polished radius scale.
• Avatars and Circles: Set a 50 percent radius to turn square images into circular avatars, then pair it with the Blob Generator for more organic shapes.
• Depth and Elevation: Combine rounded corners with shadows from the Box Shadow Generator or the Drop Shadow Generator to build modern, elevated surfaces.
• Soft and Layered UI: Use rounded corners as the base for soft interfaces, then add depth with the Neumorphism Generator for tactile, pressed-in styling.
• Backgrounds and Banners: Round the corners of hero sections and banners, and fill them with color from the Gradient Generator for finished, on-brand visuals.

This generator is maintained by TestMu AI (formerly LambdaTest), the team behind a unified testing platform, so it reflects the same attention to how CSS renders across browsers. Because corner rounding and prefixes can differ between engines, you can verify your styled components across 3000+ browsers and 10,000+ real devices to confirm the design looks right everywhere.

Frequently Asked Questions (FAQs)

What is the CSS border-radius property?

The CSS border-radius property rounds the corners of an element. It accepts one to four length or percentage values that set the radius of each corner, turning a square box into a rounded rectangle, pill, or circle without any images.

How do I use the border radius generator?

Drag the corner handles or move the slider to round the element, watch the live preview update, then enable separate corners or vendor prefixes if needed. Copy the generated border-radius CSS and paste it into your stylesheet.

How do I make a circle with border-radius?

Set border-radius to 50% on a square element, where the width and height are equal. The Max preset does this for you. A 50% radius pushes every corner inward until the box becomes a perfect circle.

What is the difference between px and percentage radius?

A pixel radius is a fixed length, so corners stay the same size regardless of element dimensions. A percentage radius is relative to the element size, so the rounding scales with the box and a 50% radius always forms a full ellipse.

Can I set each corner separately?

Yes. Enable Edit corners separately to give the top-left, top-right, bottom-right, and bottom-left corners their own radius. The shorthand border-radius output lists all four values in clockwise order starting from the top-left corner.

Is the generated CSS cross-browser compatible?

Yes. The standard border-radius property is supported in every modern browser. The generator can also add WebKit and Gecko vendor prefixes for older engines, and you can verify the result across browsers using TestMu AI.

Is the border radius generator free?

Yes, the border radius generator is completely free with no signup, login, or usage limit. Generate as much border-radius CSS as you need. The tool runs entirely in your browser and is maintained by TestMu AI (formerly LambdaTest).

Does it support elliptical corners?

Border-radius supports elliptical corners using a slash, such as border-radius: 40px / 20px, which sets the horizontal radius before the slash and the vertical radius after it. This produces an oval corner instead of a circular one for more organic shapes.