Convert pixels to rem and em values with custom base font size.
Execution runs 100% locally inside the browser sandbox using HTML5 Canvas, Web Cryptography Subtle API, and Web Workers. Zero egress.
Zero network latency. Operates completely offline with zero dependencies on third-party backend servers or cloud services.
Built according to official RFC specifications, cryptographic test vectors, and enterprise-grade data transformation standards.
Enter your base font size in pixels (default is 16px).
Type pixel measurements or paste a CSS snippet with px units.
Copy the exact calculated rem and em values or converted CSS rules.
REM units scale proportionally with the user's browser font size settings, improving web accessibility and responsive readability.
The default browser root font size is almost universally 16px (1rem = 16px).
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