CSS Border Radius Generator

What Is a CSS Border Radius Generator?

A CSS border radius generator is a visual tool that helps you create custom rounded corners for HTML elements without writing CSS by hand. The border-radius property in CSS controls how rounded the corners of an element appear, from subtle rounding on cards and buttons to perfect circles and organic blob shapes. Our free generator lets you drag sliders and see the result in real time on a live preview shape, then copy the production-ready CSS with one click.

How to Use This Border Radius Generator

Start by choosing between Simple mode (4 values, one per corner) and Advanced mode (8 values for organic shapes). In Simple mode, drag the sliders for each corner — top-left, top-right, bottom-right, and bottom-left — and watch the preview shape update instantly. Use the linked corners toggle to move all four corners simultaneously. In Advanced mode, control horizontal and vertical radii independently for each corner using the slash syntax, which enables blob-like organic shapes. Copy the generated CSS from the output panel.

Key Features

• Dual mode — Simple 4-corner mode and Advanced 8-value mode for organic shapes
• Live preview — large shape preview that updates in real time as sliders move
• Linked corners — lock or unlock corners to move all four sliders together
• Unit toggle — switch between px and % units for simple mode
• Preset shapes — one-click presets for circle, pill, leaf, chat bubble, blob, and ticket stub
• Multiple output formats — standard CSS, Tailwind CSS classes, and individual longhand properties

Understanding Border Radius Values

The border-radius shorthand accepts one to four values. A single value like border-radius: 12px applies equal rounding to all corners. Two values set top-left/bottom-right and top-right/bottom-left pairs. Four values set each corner individually in clockwise order: top-left, top-right, bottom-right, bottom-left. The advanced slash syntax (border-radius: a b c d / e f g h) controls horizontal radii before the slash and vertical radii after it, enabling asymmetric, organic shapes that are impossible with the standard four-value syntax.

Common Use Cases

• Frontend developers — generating precise border-radius CSS for cards, buttons, and modals
• UI designers — previewing and fine-tuning corner rounding before developer handoff
• CSS beginners — learning how border-radius values map to visual corner shapes
• Email developers — generating rounded-corner values for email-safe inline CSS
• WordPress users — customizing theme element corners without writing CSS from scratch

Tips and Best Practices

Use percentage values when you need shapes that scale proportionally with the element size — border-radius: 50% always makes a circle on a square element regardless of its pixel dimensions. For consistent UI components like buttons and cards, pixel values give you predictable results across different screen sizes. The 8-value advanced syntax is powerful for creating unique organic shapes, but test across browsers to ensure consistent rendering. When generating Tailwind classes, remember that Tailwind provides built-in utilities like rounded-lg, rounded-full, and rounded-t-xl for common values, and arbitrary values like rounded-[20px] for custom ones.