CalcaTools

CSS Border Radius Generator

A free visual tool to generate CSS border-radius values. Control each corner independently and see the result live. Copy the CSS with one click.

Last updated: June 2026 · Free · No sign-up required

20px
20px
20px
20px
CSS Code

Frequently Asked Questions

How does the 'Link all corners' option work?

When checked, adjusting the slider of any single corner will instantly apply that exact same border-radius value to all other three corners, producing a symmetric round shape.

What is the syntax for separate corners in CSS?

In CSS, border-radius can accept up to four values (separated by spaces), representing top-left, top-right, bottom-right, and bottom-left respectively (clockwise order).

Can I use percentage values?

This generator focuses on pixel (px) values, which are most common for precise layouts. For a perfect circle, you can set the values to 50% in your stylesheet if the element has equal width and height.

Quick reference

SyntaxEffect
border-radius: 8pxall corners 8px
border-radius: 50%circle / ellipse
border-radius: 10px 0top-left/bottom-right vs others
Four valuesTL, TR, BR, BL clockwise

Interpretation guide

LookSetting
Subtle rounding4–8px
Pill button999px
Circle50% (on a square)
Organic blobdifferent % per corner

Formula & methodology

Formula: border-radius: top-left top-right bottom-right bottom-left (clockwise from top-left)

The generator lets you set each corner radius visually and outputs the exact CSS border-radius rule.

  1. Adjust each corner’s radius and watch the live preview.
  2. Use px for fixed rounding or % for circles and blobs.
  3. The four values run clockwise: top-left, top-right, bottom-right, bottom-left.
  4. Copy the generated border-radius declaration into your CSS.

Worked example: Setting all four corners to 12px outputs border-radius: 12px;.

Frequently asked questions

How does CSS border-radius work?
It rounds the corners of an element. One value rounds all corners equally; four values set each corner clockwise from the top-left.
How do I make a perfect circle in CSS?
Apply border-radius: 50% to a square element (equal width and height).
What does the four-value syntax mean?
border-radius: a b c d sets top-left, top-right, bottom-right and bottom-left in clockwise order.
Should I use px or percent?
Use px for consistent rounding regardless of size, and percent for shapes that scale with the element, like circles and ellipses.
How do I make a pill-shaped button?
Set a very large radius such as border-radius: 999px; so the ends become fully rounded.