0.75rem=12px

With the standard browser root font size of 16px, 0.75rem equals 12px. The calculation is simply multiplication: 0.75 × 16 = 12px. This conversion is essential whenever you need to verify that a rem value in your CSS produces the exact pixel dimension specified in a design mockup, or when you are reading computed values in browser DevTools and want to translate them back into rem units.

While rem units are the preferred approach in modern CSS for accessibility and scalability, the pixel equivalent matters in day-to-day development. Browser DevTools — whether in Chrome, Firefox, or Safari — display computed styles in pixels, so knowing that 0.75rem computes to 12px lets you debug layout issues without guesswork. During design handoff, designers typically think and communicate in pixels, so converting rem values back to pixels bridges the gap between design intent and implementation.

Keep in mind that 12px is only accurate when the root font size is the browser default of 16px. If your site's CSS includes a custom font-size on the html element — say 62.5% (which makes 1rem = 10px, a common technique for easier rem math) — then the pixel equivalent will differ. Similarly, when a user sets their browser's base font size to 20px, 0.75rem will compute to 15px on their device. This flexibility is precisely why rem is recommended: it respects user preferences while maintaining proportional relationships throughout the layout.