How to Use the Font Unit Converter
Web design and print publishing use several different units to express font size. Points (pt) are the traditional unit for print documents, while pixels (px) are an absolute unit based on screen resolution. rem and em, on the other hand, are relative units - rem is always calculated from the root (html) element's font size, while em is calculated from the parent element's font size. Because the same number can render at different actual sizes depending on the base size, you need to account for the base font size (typically 16px) whenever converting between units.
This calculator applies the standard 96dpi ratio of 1pt = 1.333px, and calculates rem/em values based on the base font size you specify (default 16px). For example, with a 16px base, 1rem equals 16px and 1.5rem equals 24px. Enter a value, choose a unit, and all four units - pt, px, rem, em - are displayed simultaneously, which is handy when writing CSS or matching sizes across print and web designs.
In responsive web design, using rem lets the entire layout scale proportionally when a user adjusts their browser's default font size, which is why rem is generally recommended for accessibility-friendly CSS.
Frequently Asked Questions
1pt (point) equals about 1.333px on screen (96dpi standard). Conversely, 1px is about 0.75pt. Print documents typically use pt, while web screens use px.
rem is always calculated relative to the root (html) element's font size, while em is calculated relative to the parent element's font size. Because em can compound through nested elements, rem is generally preferred for consistent, predictable sizing.