Free CSS Border Radius Generator
Updated September 2026
Generate CSS border-radius values for rounded corners with a visual builder. Create asymmetric rounded shapes and copy the CSS — free online tool.
Verified Capabilities
Four sliders adjust top-left, top-right, bottom-right, and bottom-left radii independently.
A checkbox links all four sliders together for uniform rounding in one motion.
A sample card shows the shape live; Copy CSS grabs the generated border-radius line.
Only a single radius value per corner is supported — no toggle for the 8-value elliptical syntax.
Developers need fast, accurate utilities that slot into their workflow without friction. The CSS Border Radius Generator provides exactly that — no installation, no account, no context-switching.
Generate CSS border-radius values for rounded corners with a visual builder. Create asymmetric rounded shapes and copy the CSS — free online tool. Results are immediate — no waiting, no loading screens, no account required.
Who uses the CSS Border Radius Generator?
- Frontend developers generating border-radius values for design system components.
- UI designers testing corner rounding options to achieve the right visual weight.
- CSS beginners learning border-radius properties through interactive visual exploration.
Common uses and search terms
The CSS Border Radius Generator is frequently used for: css, border-radius, design, shape. Whether you need a quick result or are working through a longer project, the tool handles all common variations without any configuration.
Accepted input formats
The CSS Border Radius Generator accepts any standard input for this utility type. Minified, pretty-printed, and partially-formatted inputs are all handled — the tool normalises whitespace and encoding before processing. Unicode strings, multi-byte characters, special symbols, and multi-line blocks are fully supported. Very large inputs (several megabytes) may take a few extra seconds on lower-powered devices; closing unused browser tabs can free up memory for better performance. Output follows the same format conventions used by standard command-line tools and IDE extensions for this operation type.
Why use Allio Tools's CSS Border Radius Generator?
Your code and data stay entirely in your browser — nothing is logged, stored, or transmitted. The tool is completely free with no usage limits, no premium tiers, and no account required. Available in 11 languages and optimised for all screen sizes, the CSS Border Radius Generator works on desktop, tablet, and mobile with no app download needed.
See also:JSON Formatter · Base64 Encoder/Decoder · Regex Tester
How the CSS Border Radius Generator works
Use the sliders to control each of the four corner radii independently.
Check "Link all corners" to move all four together for uniform rounding.
Preview the shape live on a sample card element.
Copy the generated CSS border-radius value for direct use in your stylesheet.
Tips & tricks
- Uncheck "Link all corners" to shape asymmetric corners — useful for speech-bubble or tab-style shapes.
- The generated CSS uses a single radius per corner (border-radius: TL TR BR BL) — for elliptical corners, edit the copied value by hand using the slash syntax.
- Corner order in CSS shorthand is always clockwise starting from top-left — matching the slider labels in this tool.
- Very high radius values on a small element will visually cap out once corners meet in the middle.
Frequently Asked Questions
What is the CSS border-radius shorthand?
Single value: border-radius: 8px (all corners equal). Four values: border-radius: 10px 20px 30px 40px (top-left, top-right, bottom-right, bottom-left clockwise). Two values: border-radius: 10px 20px (TL+BR, TR+BL).
How do I create a perfect circle with CSS?
Set border-radius: 50% on a square element (equal width and height). For non-square elements, 50% creates an ellipse. Use border-radius: 50% on a div with matching width and height for a circle.
What are elliptical border radii?
CSS border-radius supports separate horizontal and vertical radii per corner using an 8-value syntax: border-radius: 10px 40px / 40px 10px creates an organic blob shape. This tool doesn't generate that syntax — it controls one radius value per corner.
Can I create organic blob shapes with border-radius?
Yes, using CSS's full 8-value syntax (different horizontal and vertical radii per corner) written by hand. This tool covers the more common single-radius-per-corner case; for elliptical/blob shapes, write the border-radius value directly.
What value creates typical "card" rounded corners?
4–8px is standard for subtle cards. 12–16px is common for modern UI cards. 24px+ is used for "pill" or "chip" style elements. Values near 50 on a small card start to look extreme.
Is my data safe when using the CSS Border Radius Generator?
Completely safe. The CSS Border Radius Generator processes everything locally in your browser. No input data, results, or usage information is ever transmitted to or stored on any server.
Can I use the CSS Border Radius Generator output in commercial projects?
Yes. The CSS Border Radius Generator is a utility tool and its output carries no licensing restrictions. You are free to use results in any project, commercial or personal.
Does the CSS Border Radius Generator follow official standards?
Yes. The CSS Border Radius Generator is built to comply with the relevant industry standard or specification for this utility type. If you encounter an unexpected result, verify your input against the specification — edge cases outside the standard may produce undefined behaviour.
Works with ChatGPT, Claude, Cursor, GitHub Copilot, VS Code, Poe and more — 106+ tools, zero data collection.