Base Font Size (px)
Line Height (REM)
Line Height Calculator
Line height controls the vertical spacing between lines of text, and modern stylesheets often define it in REM so it scales with the base font size. Translating a REM-based line height into an exact pixel value is useful when you need pixel-perfect layouts or want to match a design spec. Doing this conversion by hand means multiplying the REM value by your root font size every time a design changes.
This calculator handles that multiplication instantly, using a custom base font size if your project overrides the browser default. Enter a line height in REM and get the exact pixel equivalent right away. Every calculation runs client-side in your browser, so no value you enter is ever sent to a server.
Understanding Line Height in Web Design
Line height is the vertical spacing between lines of text, one of the most important properties for readability in web design. CSS lets you set it as a unitless multiplier, a fixed pixel value, or a relative REM value, and each behaves differently as font sizes change.
REM-based line heights scale automatically with your base font size, which keeps proportions consistent across a responsive layout. Sometimes, though, you need the exact pixel value, for example when aligning with a fixed-size element or matching a pixel-based design handoff, and that's where converting REM to PX becomes useful.
Frequently Asked Questions (FAQ)
Frequently Asked Questions