Calculate perfect vertical rhythm for web typography with our free online tool. Generate CSS for modular scales, line heights, and spacing for balanced layouts.
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Vertical Rhythm and Typography Grid Calculator
Overview
A specialized, single-file browser tool designed for web designers and front-end developers to calculate, visualize, and generate CSS for a perfectly aligned vertical typographic rhythm.
Core Features
- Live Metric Input: Real-time control over base font size, base line height, and modular scale ratio.
- Typography Preview: A side-by-side preview window rendering live text using the calculated CSS values to demonstrate visual harmony.
- Grid Overlay: A toggleable visual baseline grid (light gray lines) overlaid on the preview pane to verify alignment.
- CSS Generation Engine: Auto-generated snippet box providing the CSS variables or standard class definitions (e.g., margins, line-heights) ready for copy-pasting.
- Unit Converter: Auto-converts px to rem/em calculations based on the base font size.
UI/UX Specification
- Layout: Dashboard layout with a sidebar (left) for inputs and a main content area (right) for the preview window and CSS code output.
- Aesthetic: Clean, modern "SaaS" aesthetic. High use of white space, subtle border-radius (4px-8px), and crisp, drop-shadows on card elements.
- Responsiveness:
- Desktop: Split-screen view.
- Mobile: Stacked layout with a tabbed interface (Edit | Preview | CSS).
- Color Palette:
- Background: #F9FAFB
- Surface/Cards: #FFFFFF
- Border/Dividers: #E5E7EB
- Accent (Buttons/Active states): #4F46E5
- Text: #111827 (Primary), #6B7280 (Secondary)
Interactive Elements
- Smooth Transitions: All UI elements (inputs, toggles, layout switching) must use
transition: all 0.2s ease-in-out. - Copy Button: A prominent 'Copy CSS' button that provides visual feedback upon click (changing color and text to 'Copied!').
Technical Directives
- Architecture: Single HTML file. CSS embedded in
<style>tag, JS in<script>tag at end of<body>. - State Management: Use in-memory variables. No
localStorage,sessionStorage, or cookies allowed. - No External Popups: Use hidden DOM elements that are toggled to visible for modal dialogs (e.g., "Copied to clipboard").
- Iframe Safe: App must function within a
nullorigin iframe. Avoid all restricted APIs. - Typography: Use system fonts (Inter, system-ui) to avoid network request latency.
- Dependencies: Tailwind CSS (via CDN) for rapid, clean styling is permitted.
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Frequently Asked Questions
Everything you need to know about using this application.
What is vertical rhythm in web design?
Vertical rhythm is a design principle that ensures the spacing between text elements like paragraphs, headings, and images remains consistent across a webpage. By establishing a uniform baseline, you create a harmonious reading experience that guides the user's eye naturally down the page. Without a consistent vertical rhythm, layouts can feel disjointed and cluttered. Our calculator helps you define a base unit, often derived from your base font size and line height, to create predictable spacing that professional designers rely on to maintain visual hierarchy.
How does this calculator help with CSS?
This tool simplifies the complex math required to calculate consistent margins and line heights based on a modular scale. Instead of manually adjusting values and guessing, you can input your base font size and desired ratio to generate precise pixel or rem values that maintain a perfect grid. The tool generates clean, ready-to-use CSS snippets that you can copy directly into your stylesheet. This ensures your body text, H1, H2, and other elements all align perfectly to the vertical grid, making your responsive design look polished and mathematically balanced.
Why should I use a modular scale?
A modular scale is a sequence of numbers used to establish a harmonious relationship between font sizes on a website. By multiplying your base font size by a specific ratio, such as the Golden Ratio or a Perfect Fourth, you create a natural progression of text sizes that feel intentional and aesthetically pleasing to the reader. Using this calculator, you can visualize how different ratios affect your headings and body text immediately. This prevents the common mistake of having too many arbitrary font sizes, helping you create a unified typographic system that scales gracefully from mobile devices to large desktop monitors.
Can I use this for responsive design?
Yes, the tool is designed to assist in creating responsive typography that adapts to any screen size. By calculating the base metrics and understanding how they influence spacing, you can build CSS variables that adjust fluidly as the viewport changes, maintaining rhythm at every breakpoint. Because the calculator focuses on relative units like rems and percentages, you can easily implement the generated values into your media queries. This approach allows your vertical rhythm to remain intact regardless of the user's browser settings or device display capabilities.
