Before building Border Radius Generator, we checked a few simpler border-radius generators directly.
Per corner border radius tool: common, but rarely elliptical
Several of the ones we checked — html-css-js.com among them — let you enter "the desired curve for each corner," implying one number per corner. That's enough for a standard rounded rectangle. It's not enough for an elliptical border-radius, which the CSS spec technically supports via a horizontal/vertical split (border-radius: 50% 50% 50% 50% / 60% 60% 40% 40%-style syntax) — a single value per corner simply can't express that.
Elliptical border radius css, done properly
Every corner here has independent horizontal and vertical inputs. Leave them equal for a normal circular corner, or split them apart for a stretched, organic, blob-like shape — the generated CSS automatically switches to the slash syntax only when it's actually needed.
Border radius percent generator for responsive shapes
Fixed-pixel radius values don't scale — a 50px radius looks right on one size of box and wrong on another. Switch the unit toggle to % and the radius stays proportional to the element's own size, which is what you actually want for something like a perfect circle that has to work at multiple sizes.
