How does 8-point fancy border-radius work in CSS?

An 8-point border-radius uses a forward slash (/) to separate 4 horizontal radii from 4 vertical radii (for example, border-radius: 30% 70% 70% 30% / 30% 30% 70% 70%;). This creates asymmetrical elliptical corners and smooth organic blob shapes in pure CSS.

CSS Border Radius Generator

Create standard 4-corner curves, 8-point fancy organic blobs, and asymmetrical elliptical shapes with real-time CSS code output.

🎨 Interactive Preview & Controls

30% 70% 70% 30% / 30% 30% 70% 70%

Drag green handles or use sliders below

Fancy 8-Point Edge Controls (%) Unit: %

Radius Unit

Box Size (W × H)

Surface Style

Border Outline

Mode: 8-Point Fancy • Canvas: 240×240px

💻 Generated CSS & Code Inspector

One-Line Shorthand Value

border-radius: 30% 70% 70% 30% / 30% 30% 70% 70%;

Full CSS Rule (Editable — Paste & Click [Parse CSS]) Individual Corner Radii Breakdown

↖ Top-Left 30% / 30%

↗ Top-Right 70% / 30%

↘ Bottom-Right 70% / 70%

↙ Bottom-Left 30% / 70%

0 Chars • 0 Lines • 0 Bytes

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What Is a CSS Border Radius Generator?

A CSS Border Radius Generator is a free visual tool that helps you create rounded corners, circular buttons, and organic blob shapes for websites without writing code by hand. Instead of guessing pixel or percentage values, you drag sliders or edge handles and copy the ready-to-use border-radius CSS or Tailwind code in one click.

In modern web design, sharp 90-degree corners often look stiff. Using the CSS border-radius property softens boxes, cards, images, and buttons. With WebToolar’s generator, you can switch between Standard 4-Corner mode, Fancy 8-Point Blob mode, and Full 8-Value Elliptical mode in real time.

How to Use the WebToolar CSS Border Radius Generator

Follow these simple steps to create custom rounded corners or organic CSS shapes:

Choose Your Design Mode:
- ✦ Fancy 8-Point Blob: Drag the 4 green handles on the edges of the preview box to create smooth, asymmetrical organic blobs.
- ◰ Standard 4-Corner: Adjust the Top-Left, Top-Right, Bottom-Right, and Bottom-Left corners independently or lock them together.
- ⬭ Full 8-Value X/Y: Fine-tune horizontal (X) and vertical (Y) curves for each corner separately.
Select a Preset or Randomize: Click quick chips like [Organic Blob], [Teardrop], [Leaf], [Squircle], [Circle], or [Pill], or click 🎲 Randomize Shape for instant inspiration.
Customize Units and Box Style: Switch between %, px, rem, and em. Preview your shape with different box sizes, gradients, and borders.
Copy or Download Your Code: Click 📋 Copy CSS for standard stylesheets, 🌊 Copy Tailwind for Tailwind CSS projects, or ⬇ Download .CSS to save the file.

Understanding CSS Border-Radius Syntax (1 to 8 Values)

The CSS border-radius property is a shorthand for four corner properties: border-top-left-radius, border-top-right-radius, border-bottom-right-radius, and border-bottom-left-radius. Always remember that CSS corners follow a clockwise order starting from the top-left.

Syntax Type	CSS Example	How It Works
1 Value (All Corners)	`border-radius: 16px;`	Applies a `16px` curve equally to all 4 corners.
2 Values (Diagonal)	`border-radius: 16px 32px;`	First value (`16px`) sets Top-Left & Bottom-Right. Second (`32px`) sets Top-Right & Bottom-Left.
3 Values	`border-radius: 10px 20px 30px;`	Top-Left is `10px`, Top-Right & Bottom-Left are `20px`, and Bottom-Right is `30px`.
4 Values (Clockwise)	`border-radius: 10px 20px 30px 40px;`	Sets Top-Left (`10px`), Top-Right (`20px`), Bottom-Right (`30px`), and Bottom-Left (`40px`).
8 Values (Fancy / Elliptical)	`border-radius: 30% 70% 70% 30% / 30% 30% 70% 70%;`	Values before `/` control horizontal radii; values after `/` control vertical radii.

How Does 8-Point Fancy Border Radius Work?

Most developers know how to round 4 corners, but CSS also supports 8-value elliptical border radius using a forward slash (/).

css/* Horizontal Radii / Vertical Radii */border-radius: 30% 70% 70% 30% / 30% 30% 70% 70%;

Before the slash (30% 70% 70% 30%): Controls the horizontal curve of the Top-Left, Top-Right, Bottom-Right, and Bottom-Left corners.
After the slash (30% 30% 70% 70%): Controls the vertical curve of the Top-Left, Top-Right, Bottom-Right, and Bottom-Left corners.

When adjacent corners add up to 100% (for example, 30% + 70% = 100%), the edges blend into a continuous, smooth curve without flat sides. This creates an organic CSS blob using pure CSS—no heavy SVG files or PNG images required.

Popular CSS Border Radius Cheat Sheet (Copy & Paste)

Here are the most common shapes used in modern UI design:

Perfect Circle (on a square box): border-radius: 50%;
Pill / Capsule Button: border-radius: 9999px;
Modern App Card / Squircle: border-radius: 24px;
Organic Hero Blob: border-radius: 30% 70% 70% 30% / 30% 30% 70% 70%;
Water Teardrop / Map Pin: border-radius: 50% 50% 50% 0% / 50% 50% 50% 0%;
Organic Leaf Shape: border-radius: 0% 75% 25% 75% / 75% 50% 50% 25%;

Which CSS Unit Should You Use: `px`, `%`, `rem`, or `em`?

Choosing the right unit ensures your design looks great on mobile phones, tablets, and desktop screens:

Percentage (%): Best for circles, ellipses, and 8-point organic blobs. Percentage radii scale automatically with the width and height of the element.
Pixels (px): Best for cards, modals, inputs, and buttons when you want consistent corner rounding regardless of box size.
rem (Root EM): Best for accessible, scalable design systems. Corners scale smoothly when a user changes their browser font size.
em: Best for badges, tags, and buttons where the corner radius should grow or shrink proportionally with the element’s own text size.

Key Features of WebToolar’s CSS Border Radius Tool

3-in-1 Generator: Combines a 4-corner generator, an interactive 8-point blob maker, and an 8-value X/Y editor in one clean workspace.
Reverse CSS Parser: Already have a border-radius rule? Paste it into the code editor and click [Parse CSS] to edit it visually.
Live Morph Animation Preview: Click ▶ Animate Morph to preview how your organic blob looks with smooth @keyframes CSS animation.
Tailwind CSS Ready: Export arbitrary Tailwind classes like rounded-[30%_70%_70%_30%/30%_30%_70%_70%] in one click.
Legacy Browser Support: Toggle [+ Vendor Prefixes] to include -webkit-border-radius and -moz-border-radius when needed.
100% Free & Privacy-Friendly: Runs entirely in your browser with zero server uploads.

FAQs: CSS Border Radius Generator

How do I make a perfect circle in CSS?

To make a perfect circle in CSS, give your element an equal width and height (for example, 200px by 200px) and set border-radius: 50%;. If the width and height are different, border-radius: 50%; will create an oval instead of a circle.

What is the difference between `border-radius: 50%` and `border-radius: 9999px`?

On a rectangular button, border-radius: 50% creates an oval shape because percentages are calculated from the width and height separately. In contrast, border-radius: 9999px creates a pill-shaped button with straight top/bottom edges and fully rounded left/right ends.

Why is `border-radius` not working on my image or table?

If border-radius is not showing on a container with a child image, add overflow: hidden; to the parent container or apply border-radius directly to the <img> tag. For HTML tables, add border-collapse: separate; so rounded corners render properly.

Are CSS blobs better than SVG blobs for page speed?

Yes. Pure CSS blobs created with 8-point border-radius require only a single line of CSS code (under 60 bytes). They load instantly, require zero extra HTTP requests, and can be animated smoothly with CSS @keyframes.

Does 8-value `border-radius` work in all modern browsers?

Yes. All major browsers—including Chrome, Firefox, Safari, Edge, and mobile browsers—fully support both 4-value and 8-value (/ slash syntax) border-radius properties without requiring vendor prefixes.