Fluid Type Calc is a free online tool that generates CSS clamp() expressions for fluid typography — type that scales smoothly between two viewport widths instead of jumping between breakpoints. Type four numbers, watch the preview breathe at any screen width, and copy production-ready CSS in one click. No account, nothing leaves the page.

Type scale

Min font size px

Max font size px

Min viewport width px

Max viewport width px

Live preview

Type that scales beautifully

Fluid type grows and shrinks with the screen — no breakpoints, no jumps. Drag the slider below to see this heading breathe from a phone to a desktop.

Simulated viewport 768px

Presets

Presets run over 360 → 1280px viewports. The page opens on the 16 → 24px default, not a preset.

CSS output

How it works

Slope — how fast the type grows: (max size − min size) ÷ (max viewport − min viewport), expressed in vw units. Steeper slope, faster growth.
Intercept — the px anchor the vw term is added to, so the line passes exactly through your min size at your min viewport.
clamp() — pins the result: below the min viewport the size stays at your minimum, above the max viewport it stays at your maximum, and between them it glides along the line.
Prefer rem? — divide every px value by 16 (e.g. 16px → 1rem, 24px → 1.5rem) and keep the vw term as-is.