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CSS Tool

CSS Border Radius Generator

Visually set corner radius values and watch a live preview update in real time — from subtle card corners to perfect circles. Copy the CSS and drop it straight into your Canvas HTML Template.

Presets

8px
border-radius: 8px;

What is CSS border-radius?

border-radius is a CSS property that rounds the corners of an element’s border box. A value of 0 gives sharp corners; increasing the value creates increasingly rounded corners until you hit a circle at 50% on a square element.

In Bootstrap 5, the .rounded-* utility classes apply border-radius values ranging from .rounded-1 (0.25rem) to .rounded-5 (3rem), plus .rounded-circle and .rounded-pill. When you need a value outside this range, a custom CSS declaration is your best option.

The Canvas HTML Template uses border-radius extensively on cards, buttons, image thumbnails, and team photo blocks. Many components expose a CSS variable like --cnvs-border-radius which you can override globally or per-section with a single line in a <style> block.

The four-value shorthand border-radius: TL TR BR BL lets you create asymmetric shapes — great for organic, modern aesthetics. The squircle preset (30% 70% 70% 30% / 30% 30% 70% 70%) is a popular app-icon style shape that sits between a circle and a square.

How to use this tool

  1. 1

    Choose Simple mode for uniform corners or Advanced mode to set each corner individually.

  2. 2

    Toggle between px (fixed size) and % (relative to element dimensions) units.

  3. 3

    Drag the slider(s) and watch the teal preview square morph in real time.

  4. 4

    Pick a preset — None, Subtle, Card, Pill, Circle or Squircle — to jump to a common value.

  5. 5

    Click Copy CSS to grab the border-radius declaration and paste it into your Canvas template or stylesheet.

Common border-radius values

NameValueUse Case
None0Tables, full-bleed images
Subtle4pxInput fields, tags
Card8px – 12pxBootstrap cards
Modal16pxDialogs, panels
Pill9999pxCTA buttons
Circle50%Avatars, icons
Squircle30% 70% 70% 30% / ...App icons

Frequently Asked Questions

What is border-radius in CSS?

The CSS border-radius property rounds the corners of an element's outer border edge. You can set a uniform radius for all four corners, or specify each corner individually using the shorthand: border-radius: top-left top-right bottom-right bottom-left. It accepts px, %, em, and rem values.

How do I make a perfect circle with border-radius?

Set border-radius: 50% on an element with equal width and height. For example: width: 80px; height: 80px; border-radius: 50%. This is the standard technique for circular avatars and icon containers in Bootstrap and Canvas HTML templates.

What is the difference between px and % for border-radius?

Pixel values (px) create a fixed radius regardless of element size — good for consistent card corners. Percentage values (%) are relative to the element's dimensions — 50% always creates a circle on square elements. For buttons, a fixed px value like 8px maintains consistent corners even when the button size changes, while % can make small buttons look very round.

How do I create a pill shape with CSS?

Use a very large border-radius value like 9999px or 100vw. Because the browser caps the radius at half the element's shortest dimension, any sufficiently large value produces a perfect pill shape. Bootstrap 5 uses .rounded-pill which applies border-radius: 50rem.

How do I set different border-radius per corner?

The border-radius shorthand accepts up to four values: border-radius: top-left top-right bottom-right bottom-left. For example: border-radius: 12px 4px 12px 4px. You can also use individual properties: border-top-left-radius, border-top-right-radius, border-bottom-right-radius, border-bottom-left-radius.

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