# CSS Fluid Typography Clamp Calculator Generate a clamp() expression from min and max viewport and font-size bounds, with copy-ready CSS and preview data > Canonical page: https://elysiatools.com/en/tools/css-fluid-typography-clamp-calc - **Category:** Design - **Keywords:** css, clamp, fluid typography, responsive type, design system ## Overview Calculates the preferred vw slope and intercept for fluid typography, then returns a copyable clamp() expression plus preview HTML for responsive inspection. ## Inputs - **Minimum Viewport** (number) - **Maximum Viewport** (number) - **Minimum Font Size** (number) - **Maximum Font Size** (number) - **Root Font Size** (number) - **Sample Text** (text) ## When to use - When designing responsive websites that require typography to scale smoothly between mobile and desktop viewports without abrupt media query breakpoints. - When building a modern design system that uses fluid type scales to maintain visual hierarchy across diverse device sizes. - When you need to calculate the exact CSS clamp() formula using rem units and viewport width percentages without manual math. ## How it works - Enter your target minimum and maximum viewport widths in pixels. - Specify your desired minimum and maximum font sizes, along with your project's root font size. - The calculator computes the slope and intercept to generate a copy-ready CSS clamp() expression. ## Use cases - Creating fluid hero section headlines that scale down gracefully on mobile screens. - Establishing a responsive body text scale that adapts to tablet and desktop viewports. - Defining fluid spacing, margins, and paddings within a responsive CSS layout grid. ## Frequently asked questions ### What is CSS fluid typography? Fluid typography is a web design technique where font sizes scale smoothly between a defined minimum and maximum size based on the viewport width. ### How does the clamp() function work in CSS? The clamp() function takes three parameters: a minimum value, a preferred value (usually calculated using viewport units), and a maximum value, preventing the font from scaling outside these bounds. ### Why does the calculator convert pixels to rem units? Using rem units for typography is a best practice for accessibility, ensuring that text scales correctly if a user changes their browser's default font size settings. ### What is the root font size setting used for? The root font size (defaulting to 16px) is used as the base value to convert pixel inputs into relative rem units for the final CSS output. ### Can I use this calculator for properties other than font-size? 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