Free & Private Online Browser Utility
Fluid Typography & CSS Clamp Calculator
Generate exact mathematical CSS clamp() expressions for responsive fluid typography, fluid spacing, and dynamic layout padding. The calculator solves the linear interpolation equation (y = mx + b) between minimum and maximum viewport breakpoints, calculating exact rem base values and viewport width (vw) slope rates in real time. Copy pure CSS declarations, CSS custom properties, and Tailwind arbitrary classes without server calls.
How to use
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Step 1: Set Viewport Range
Specify your minimum mobile breakpoint (such as 360px) and maximum desktop breakpoint (such as 1280px).
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Step 2: Define Value Range
Input minimum and maximum dimensions for font-size, padding-block, margin, or layout gaps in pixels or rems.
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Step 3: Copy CSS or Tailwind Output
Copy the calculated clamp() formula, CSS custom property declaration, or Tailwind arbitrary class.
Worked example
Input: Font scale from 16px at 360px width to 36px at 1280px width
Output: font-size: clamp(1rem, 0.5109rem + 2.1739vw, 2.25rem);
Linearly scales between 16px on mobile viewports and 36px on desktop displays.
Tips & limits
- Using rem units for minimum and maximum values allows users with custom browser font scales to resize text properly.
- CSS clamp() works for layout spacing, gap, and padding-block just as effectively as typography.
- Setting root font size to 16px matches the default document body font scale across modern web browsers.
Common problems
- Maximum viewport breakpoint is smaller than minimum breakpoint
Ensure the desktop width value is strictly greater than the mobile viewport width to prevent negative slope values.
- Clamp text expands beyond intended container width
Clamp locks dimensions at maximum size once the viewport passes the desktop width boundary.
Frequently Asked Questions (FAQ)
What is the mathematical formula behind CSS clamp() fluid typography?
The formula calculates slope = (maxSize - minSize) / (maxWidth - minWidth) and yIntersection = -minWidth * slope + minSize, producing clamp(min, yIntersection + slope * 100vw, max).
Why is fluid typography preferable to breakpoint media queries?
Media queries trigger discrete step changes that can cause layout jitter. CSS clamp() scales text smoothly at every single pixel dimension between breakpoints.
Can I use the output directly in Tailwind CSS?
Yes. The generator produces Tailwind arbitrary utility classes like text-[clamp(...)] ready to drop into JSX elements.