Generate CSS border-radius for rounded shapes and pure CSS triangles. Live preview with copy-ready code.
CORNERS
12px
Quick Shapes
Direction
80px
80px
About CSS Shape Generator
Generate CSS code for two fundamental CSS shapes: rounded corners using border-radius and pure CSS triangles using the border trick. Both techniques are widely used in UI design for buttons, cards, tooltips, and decorative elements.
How CSS Triangles Work
CSS triangles exploit the fact that element borders meet at angles. By setting an element to zero width and height and making three borders transparent while one is colored, the colored border appears as a triangle. No images or SVG needed.
Frequently Asked Questions
The CSS border-radius property rounds the corners of an element. You can set all four corners at once or individually. Using 50% on a square element creates a perfect circle; 999px or a very large value creates a pill/stadium shape.
CSS triangles are used as tooltip arrows, dropdown carets, decorative dividers, and speech bubble tails. They require no image assets and scale perfectly at any size.
Yes - border-radius works on any HTML element. It applies to the element's background and border, but not to content that extends beyond the box unless you also add overflow: hidden.
For simple directional arrows and carets, CSS triangles are lighter and require no extra files. For more complex shapes, rotated triangles, or when you need the triangle to be interactive with click areas, SVG is more flexible and accessible.
About CSS Shape Generator — CSS Shape Generator Online
A CSS shape generator online lets you visually create geometric shapes — circles, triangles, pills, and polygons — and get production-ready CSS code instantly. No design software, no SVG files, and no images are required. UI developers, front-end engineers, and web designers use a CSS shape generator online to prototype layouts, build icon-free decorative elements, and generate tooltip arrows or section dividers without leaving the browser.
Pure CSS shapes have compelling advantages over images or SVGs for simple geometric elements. They are infinitely scalable without quality loss, have literally zero file size impact (the shape is defined entirely by CSS properties), can be animated with CSS transitions and keyframes, and are trivially themeable via CSS custom properties. This tool covers the two most commonly needed shapes in real-world UI work: rounded corners via border-radius and directional triangles via the CSS border trick.
How to Use the CSS Shape Generator
Click the Border Radius tab to generate rounded corner shapes, or the CSS Triangle tab to generate directional triangles.
For border-radius: use the All Corners slider for uniform rounding, or uncheck Lock All to set each corner individually. Choose a unit (px, %, rem) and pick a box color.
For triangles: click a direction arrow to set which way the triangle points, then adjust the Width and Height sliders and choose a color.
The live preview updates instantly as you change any control, so you can see the exact shape before copying the code.
Click Copy CSS to copy the complete, ready-to-paste CSS rule for the shape into your clipboard.
Shape Types and Their CSS Techniques
Each shape type in this CSS shape generator online uses a different CSS mechanism. Understanding which technique produces which shape helps you choose the right approach for your project.
Rounded corners (border-radius): The border-radius property rounds the corners of any block element. A single value applies equally to all four corners. Using 50% on a square element produces a perfect circle; a large value like 999px creates a pill or stadium shape. This property is supported in all browsers without any vendor prefixes.
CSS triangles (border trick): A zero-width, zero-height element with borders on all four sides forms a diamond made of four triangles meeting at the center. By making three of those borders transparent and leaving one colored, you isolate one triangle. Adjusting the relative border widths controls the proportions of the triangle — making the perpendicular borders thicker widens it, making them taller narrows it.
Directional variants: The eight direction buttons (up, down, left, right, and four diagonals) automatically configure the correct border assignments. Diagonal triangles use only two border declarations instead of three, producing a right-angle triangle rather than an isosceles one.
Tips for Getting the Best Results
Use these tips to make the most of this CSS shape generator online and integrate generated shapes smoothly into real projects.
Use percentage units for circles and pills: When creating a circle with border-radius, set the value to 50% rather than a fixed pixel value. This ensures the shape remains perfectly circular even if the element's dimensions change. For a pill shape, border-radius: 999px works on any height without calculation.
Place CSS triangles on pseudo-elements: In production, CSS triangles are almost always applied to ::before or ::after pseudo-elements rather than real DOM elements. This avoids adding empty markup to your HTML. Set the pseudo-element to content: '', display: block, and position: absolute, then use the generated border CSS.
Maintain contrast for colored shapes: When choosing a color for your triangle or rounded box, ensure there is sufficient contrast against the background it will sit on. CSS shapes used as tooltip arrows should match the tooltip background color so the border illusion works correctly.
Animate with CSS transitions: Border-radius shapes are easily animated. Add transition: border-radius 0.3s ease to a button to create a smooth rounded-to-pill animation on hover. Triangles can be rotated with transform: rotate() for animated expand/collapse indicators.
Combine with box-shadow for depth: Rounded shapes gain depth when paired with box-shadow. A circle with a subtle box-shadow becomes a floating action button. Remember that box-shadow follows the border-radius curve, so the shadow also appears rounded.
Why Use a CSS Shape Generator Online
Generating CSS shapes by hand — especially triangles — requires knowing the exact border syntax and mentally previewing the result. A CSS shape generator online eliminates that trial-and-error cycle entirely. You interact with a live visual preview and sliders, and the tool writes the CSS for you. No memorizing the border trick formula, no guessing at values. The result is copy-paste ready code that works in production immediately.
This tool is especially useful for developers who need to add simple decorative elements without reaching for image files, for designers who are learning CSS, and for anyone building tooltips, dropdown indicators, section separators, or card components where CSS-only shapes keep the asset count low and the codebase clean.
Frequently Asked Questions about CSS Shape Generator
CSS shapes are resolution-independent, rendering perfectly on retina and HiDPI displays at any size. They have zero file size impact, can be restyled instantly with a single CSS variable change, and are animatable with CSS transitions. For simple geometric shapes like triangles, arrows, and circles, CSS is always a lighter solution than SVG or image files, and it removes one network request from the page entirely.
Yes. For border-trick triangles, change the value of the colored border property. For border-radius shapes, change the background-color. Both work perfectly with CSS custom properties, so you can tie the shape color to a design token like var(--color-primary) and it will update automatically when the theme changes.
Yes. The border trick for triangles has been supported in all browsers for well over a decade and requires no vendor prefixes. The border-radius property is equally universal. The CSS generated by this tool works in every modern browser including Chrome, Firefox, Safari, and Edge, and also in older browsers if you need to support legacy environments.
Yes. Apply the shape CSS to a ::before or ::after pseudo-element with content: '', position: absolute, and set the parent to position: relative. This overlays the CSS shape as a decorative background element without adding any real DOM nodes, keeping your HTML clean and semantic.
Yes, completely free with no limitations. There are no sign-up requirements, no usage caps, and no premium features behind a paywall. Generate as many shapes as you need and copy the CSS at no cost.
No. All shape generation and CSS output runs entirely in your browser using JavaScript. Nothing is sent to any server. The tool works offline once the page has loaded.
Yes. The generated CSS is standard CSS that you can paste into any stylesheet, including custom CSS layers in Tailwind projects. For Tailwind, you would typically add the shape styles as a component class or apply them via a @layer components block. The border-radius values also map directly to Tailwind's rounded- utilities for common presets.
Yes. The CSS shape generator is fully responsive. On small screens the layout adapts so the preview and controls stack vertically, making it easy to use on a phone or tablet. Touch controls work for all sliders and buttons.