About This Tool
Documentation
What does this tool do?
A responsive geometry utility that calculates missing width or height values based on standard and custom aspect ratios. Computes modern CSS `aspect-ratio: W / H` declarations and legacy responsive intrinsic ratio wrapper classes (`padding-top: (H/W)*100%`) with video and image dimension presets (1080p, 4K, Ultrawide, Social formats).
When should you use it?
Use this tool to prevent Cumulative Layout Shift (CLS) in responsive image galleries, format responsive iframe video containers, calculate banner dimensions, or standardize cross-platform social media card layouts.
Key Capabilities & Features
Highlights
Calculate dimensions and proportions for standard aspect ratios (16:9, 4:3, 1:1, 21:9, 9:16)
Interactive pixel width and height scaling with instant ratio recalculation
CSS aspect-ratio property code generation with legacy padding-bottom fallback snippets
Responsive image and video embed container dimension calculator
Visual preview box dynamically resizing to matching proportions