The CSS clamp() function is one of the most useful tools in modern CSS, but the math to get a correct preferred value is tedious to do by hand. What clamp() actually does clamp(minimum, preferred, maximum) locks a value between a floor and ceiling while letting it scale proportionally between them based on viewport width. For fluid typography, the preferred value is a linear interpolation between two known points: the size you want at your smallest viewport, and the size you want at your largest

How CSS clamp() works (and a free generator that does the math for you)
Michael Kelly
