Calculate aspect ratios, legacy padding-top hacks, and modern CSS aspect-ratio rules.
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.
Select standard presets like 16:9, 4:3, 1:1, 9:16, 21:9, or enter custom width/height.
Preview how the element resizes responsively while locking its proportional aspect ratio.
Copy modern aspect-ratio rules or legacy padding-top container stylesheets.
In CSS, percentage padding is calculated relative to the parent container's width, allowing (Height / Width * 100)% to maintain fixed proportions.
Yes, the native aspect-ratio property is supported in all modern versions of Chrome, Safari, Firefox, and Edge.
Zero-egress companion tools in the Developer Tools suite
Format, validate, repair, and minify JSON data instantly.
Decode, verify claims, inspect headers, and check token expiry.
Test regex patterns with flags, group captures, and live matches.
Compare text or source code side-by-side with visual diffs.
