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CSS clamp calculator

Create fluid font sizes and scrub the viewport to preview the interpolation.

360px1280px
Type that grows
with your screen.

24px at a 820px viewport

The specimen shows the calculated size at the simulated viewport. Its container fits your screen.

Generated CSS
font-size: clamp(1rem, 0.608696rem + 1.73913vw, 2rem);
Processed on your device

How it works & useful details

How to use this tool

Set minimum and maximum font sizes with viewport endpoints. Scrub the viewport slider to see the calculated size between them.

Supported values and limitations

All endpoint inputs use CSS pixels. Rem output uses the explicit root-size assumption; changing user font settings changes endpoints. The live sample uses the calculated pixel size for the selected simulated viewport. Coefficients are rounded to six decimal places. Test zoom and text resizing in your own page.