CSS Clamp Generator
Generate a CSS clamp() expression from minimum and maximum viewport/value pairs and show the linear formula used between them. It is a fluid sizing helper, not a visual regression test.
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What this tool is for
Generate a CSS clamp() expression from minimum and maximum viewport/value pairs and show the linear formula used between them. It is a fluid sizing helper, not a visual regression test.
How to use
- Enter minimum and maximum viewport widths.
- Enter the corresponding minimum and maximum sizes with compatible units.
Copythe expression and test it at endpoints and intermediate widths in the real layout.
Example
Map 16px at 320px to 24px at 1280px and verify that the generated preferred term stays between those bounds.
FAQ
Does clamp replace responsive testing?
No. Test wrapping, zoom, and user font settings in the real component.
Why include min and max?
They bound the interpolated preferred value outside the chosen viewport range.
Reproducible examples
Known inputs and expected results
Run these examples in the workspace above and compare the result with the documented output.
Fluid font size
- Input
- 16px at 320px; 24px at 1280px
- Options
- Use linear interpolation and px output.
- Action
Generateclamp().- Expected output
- A clamp bounded by 16px and 24px with a preferred term equivalent to about 13.3333px + 0.8333vw.
- Explanation
- The preferred line passes through both selected viewport/value points.
Rem output
- Input
- 16px at 360px; 32px at 1440px
- Options
- Choose rem output with a 16px root font size.
- Action
Generateand test endpoints.- Expected output
- clamp(1rem, 0.6667rem + 1.4815vw, 2rem).
- Explanation
- The input sizes are pixel values and the selected root size converts the bounds and intercept to rem; that root assumption must match the receiving design system.
Error or unsupported case
Degenerate range
- Input
- Viewport minimum 768; viewport maximum 768
- Expected error or limit
- Equal viewport points cannot define a slope and are rejected.
- Safer alternative
- Choose two distinct viewport widths or use a fixed CSS value.
When not to use this tool
- Replacing real responsive, zoom, or wrapping tests
- Nonlinear type scales, container queries, or mixed-unit design systems without review
Algorithm and assumptions
The preferred value is a straight line between two points, bounded with clamp(); rounding affects the emitted coefficients and rem output uses the stated root-pixel basis.
Input and output
Input is two viewport/value points. Output is a bounded CSS clamp() expression and formula details.
Supported formats and behavior
- Linear interpolation
- px and rem output contexts
- Copy-ready CSS
Limits
- No container-query or typography quality judgment
- Mixed root-font assumptions require review
Edge cases and common errors
- Equal viewport widths cannot define a slope
- Reversed ranges are rejected
- Rounding can slightly alter intermediate values
Release testing
Checks cover a known linear vector, endpoints, invalid/equal ranges, decimal values, copy, and reset.
Privacy boundary
The input and result stay in this browser session. ZZP Box does not upload or store the values entered in this tool.
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