Turn print-style point sizes into EM values so your type scales with the parent. Enter a base font size and your point value to get the EM result.
Points are fixed (1pt = 1/72 inch). Browsers treat 1pt as 4/3 px. EM is relative to the parent font size, so the same EM value looks bigger or smaller depending on context.
Formula: convert pt to px with pt × (4/3), then divide by base px to get em.
Use this when you have a design in points (e.g. from print or a style guide) and you want CSS that scales with the root or a parent. Keep base font size set to the parent you care about (often 16px for the document).
