CSS Border Radius Generator
CSS Border Radius Generator — Round Corners Perfectly, Visually
Rounded corners are one of the defining details of modern interface design — they soften a layout, make buttons look tappable, and give cards a friendly, polished feel. But dialing in the right border-radius by hand means editing CSS, reloading, and squinting at pixels. This free generator replaces that with instant visual feedback: move the sliders, watch the corners round in real time, and copy clean, cross-browser CSS when it looks right. You can round all four corners together or shape each one independently, all in your browser with no signup.
Understanding the border-radius Property
At its simplest, border-radius takes one value and rounds all four corners of an element by the same amount. But its real power is in independent control: you can give each corner — top-left, top-right, bottom-right, and bottom-left — its own radius. That flexibility is what lets you move beyond uniformly rounded boxes to create tabs with only the top corners rounded, speech-bubble shapes, asymmetric cards, and more. Writing the multi-value syntax by hand is error-prone; this tool generates it correctly from your visual adjustments.
Pixels Versus Percentages
| Unit | Behavior | Best for |
|---|---|---|
| Pixels (px) | Fixed corner size regardless of element dimensions | Buttons, cards, inputs — consistent look |
| Percentages (%) | Radius scales with the element's size | Circles, pills, avatars that adapt |
The choice matters. A fixed pixel radius keeps every card in a grid looking identical. A percentage radius, by contrast, is how you make shapes that respond to size — most importantly, the circle.
Making Circles, Pills, and Custom Shapes
Some of the most useful shapes in UI design come straight from border-radius. Apply 50% to a square element and it becomes a perfect circle — the standard technique for round avatars and icon buttons. Apply a large radius, or 50%, to a wide rectangle and you get a pill shape, ideal for tags, badges, and modern buttons. Round only the top two corners and you have a tab or a card header. Because the generator shows the result live, you can experiment with these shapes and understand exactly which values produce them, rather than guessing.
Why Rounded Corners Feel Better
There is real psychology behind the trend. Sharp corners read as hard and technical; rounded corners read as soft, approachable, and safe — our eyes process gentle curves more easily than hard angles. That is why nearly every major design system uses rounded corners on buttons, cards, and inputs. The amount of rounding sets the tone: a small radius feels crisp and professional, a large radius feels playful and friendly. Choosing the right value for your brand is a subtle but meaningful design decision, and seeing it live helps you get the feel exactly right.
Keeping Corners Consistent Across a Design
One mark of a polished interface is consistent corner rounding. When buttons, cards, inputs, and modals all share the same radius (or a small, deliberate set of radii), the design feels intentional and unified. When they vary randomly, it looks sloppy even if each element is fine on its own. A practical approach is to decide on one or two standard radius values early — say a small one for inputs and buttons and a slightly larger one for cards — and reuse them everywhere. This generator makes it easy to lock in those values and copy them consistently.
A Detail That Pairs With Others
Border-radius rarely works alone. Rounded corners look their best combined with a subtle shadow that lifts the element off the page and a considered color scheme. Together, radius, shadow, and color form the core of a modern component's look. Designing them in concert — rounding the corners, adding a soft shadow, applying harmonious colors — is how flat boxes become the polished cards and buttons you see in well-crafted interfaces.
Clean, Reliable Output
The CSS this tool produces uses the standard border-radius property, supported by every modern browser without prefixes. You can paste it directly into a stylesheet, a CSS-in-JS block, or an inline style, and it will render identically across devices. Whether you generate a single value for all corners or a full four-value declaration for a custom shape, the output is production-ready.
Free, Private, and Instant
Design as many rounded shapes as you like at no cost and with no account. Because it runs entirely in your browser, it is fast and completely private. Rounded corners are a small detail with an outsized effect on how finished your interface feels, and getting them right takes seconds here. Pair this with our Box Shadow Generator, CSS Gradient Generator, and Color Palette Generator to build a cohesive, modern design system from the ground up.