Free Border Radius Consistency Checker Standardize Your UI Corners

Open your browser's inspector on almost any production web application and inspect the border radii of the first ten components you find. Most codebases reveal something like this: buttons at 6px, cards at 12px, inputs at 8px, modals at 16px, badges at 9999px, tooltips at 4px, dropdowns at 10px. Seven components, seven different values, zero system. This is the border radius problem — and it compounds silently as products scale.

Why Border Radius Consistency Matters

Border radius is one of the primary visual signals that gives a UI its personality — whether it feels sharp and businesslike, soft and friendly, or playfully rounded. When radius values scatter across arbitrary numbers, the UI sends contradictory signals to users. A card with 12px corners next to a button with 6px corners creates a subtle visual discord that users can't articulate but absolutely feel.

The maintenance burden is equally significant. When radius values aren't standardized, every new component becomes a judgment call. Should this tooltip be 4px or 6px? Different engineers answer differently on different days, and the inconsistency compounds. By the time a design system audit happens, the codebase might contain 15 distinct radius values for what should be 5–7 semantic tokens.

How the Consistency Checker Works

The checker applies a three-step analysis to your radius values:

• 1Base unit detection — The tool computes the greatest common divisor of your non-zero, non-full radius values to infer the base unit your codebase has been implicitly using. If your values are 4, 8, 12, and 16px, the detected base is 4px. You can override this with the manual control.
• 2Scale generation — From the base unit, the tool generates a semantic radius scale: none (0), sm (0.5×), md (1×), lg (1.5×), xl (2×), 2xl (3×), 3xl (4×), and full (9999px). Each step maps to a named token so engineers reference tokens, not pixel values.
• 3Value snapping and scoring — Each of your radius values snaps to the nearest step in the generated scale. The consistency score penalizes large deviations from scale steps and rewards reduction in unique value count. A score of 85+ is consistent. Below 35 requires significant standardization work.

Standard Radius Systems Used by Major Design Systems

Every mature design system makes an explicit decision about its radius language. Here's how the industry leaders approach it:

Integrating a Custom Radius Scale in Tailwind CSS

Tailwind's default rounded utilities (rounded-sm through rounded-3xl) use a 4px base. You can extend or replace these in your config using the generated output from this tool. Add the config to theme.extend.borderRadius to merge with defaults, or theme.borderRadius to replace them entirely:

{/* Use semantic token names instead of pixel values */}
<button className="rounded-md px-4 py-2">   {/* 8px on 4px base */}
<div className="rounded-lg p-6">            {/* 12px on 4px base */}
<input className="rounded-sm border" />     {/* 2px on 4px base */}
<span className="rounded-full px-2">       {/* 9999px — pill */}

{/* Override for dark/brand theme by changing base unit */}
{/* 4px base = crisp enterprise UI */}
{/* 8px base = friendly consumer UI */}
{/* 16px base = very soft/rounded style */}

Once you adopt a token-based radius system, the utility class names become semantic: rounded-sm means "subtle rounding," rounded-lg means "prominent rounding for cards," and rounded-full means "pill/circle." The actual pixel values can change per brand without updating a single component file.

In Tailwind v4, you define your radius scale using @theme in your CSS file, which creates CSS custom properties that Tailwind uses to generate utility classes. The CSS variables output from this tool is directly compatible with this approach.

Radius Conventions Every UI Engineer Should Know

Frequently Asked Questions

Border radius inconsistency is one of the easiest design system problems to fix — once you can see it. Audit your radius values above, apply the standardized scale, and eliminate one more source of visual noise from your UI. It takes five minutes and improves the coherence of every component on the page.