Design Tools · CornerKit

Border-Radius Generator

Shape every corner — from subtle rounding to pills and organic blobs — with a live preview and copy-ready CSS.

Corners

Preview

px
px

CSS

Tailwind class

Presets

Common shapes to start from.

Border-Radius Guide

How the shorthand works and when to use each unit.

Corner Order

top-left top-right bottom-right bottom-left

Values go clockwise from the top-left. Two values mean "top-left & bottom-right", then "top-right & bottom-left".

Elliptical Corners

40px 10px / 20px 60px

Values before the slash set each corner's horizontal radius; values after set the vertical radius.

px vs %

16px · 50%

px keeps corners the same size on any box. % is relative to the box's width (horizontal) and height (vertical).

Pills & Circles

9999px · 50%

A huge px value makes a pill on any rectangle. 50% makes a circle on a square and an ellipse on a rectangle.

Overlapping Radii

auto-scaled

If two corners on one side add up to more than the side, browsers scale all radii down evenly so they fit.

Nested Corners

inner = outer − padding

For a rounded element inside another, subtract the padding from the outer radius so the curves stay parallel.

Why CornerKit?

CornerKit is a fast, lightweight corner designer for web designers and developers — dial in every corner visually instead of trial and error in the browser's dev tools.

All processing happens entirely in your browser. Nothing leaves your device.

100% Private — nothing is sent to a server
Per corner — or link them all together
Elliptical — eight values for organic shapes
Shortest CSS — the shorthand is trimmed for you
Tailwind ready — copy an arbitrary-value class
Card16px
Pill button9999px
Avatar50%
Tab12px 12px 0 0
Blob30% 70% … / …