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Layout Aspect Ratio Calculator

Calculate video aspect ratio dimensions from width or height. Convert 16:9, 4:3, 2.35:1 cinema, and vertical 9:16 for social media and broadcast formats.

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Inputs that matter
Width and height in pixels, with an optional ratio/size preset and the link control for proportional resizing.
Output to expect
A simplified aspect ratio, scaled preview, pixel count, diagonal in pixels and a CSS aspect-ratio declaration.
How it works
The ratio reduces the entered whole-pixel dimensions. When linking is on, changing one dimension adjusts the other to retain the current proportion, rounded to a whole pixel.
  • Unlock the dimensions when you want to change the ratio itself. Presets replace the dimensions; review both values afterwards.
  • The diagonal is measured in pixels, not inches. Copy includes the dimension summary as well as the CSS declaration.
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Projects using Layout Aspect Ratio Calculator

This tool is part of these guided projects. Each project provides step-by-step instructions with checklists and all the tools you need in one place.

Responsive Interface Decision Record

Coordinate one responsive interface through real content and people, layout requirements, bounded CSS/unit scenarios, representative reflow and interaction testing, controlled implementation, and named acceptance.

6 steps13 toolsStart project

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Reference & details

How it works

Height from Width

16:9 → ratio 1.778. Width 1920 → height 1080.

Height = Width ÷ Aspect Ratio (W:H as decimal W/H)

Width from Height

Vertical 9:16: height 1920 → width 1080.

Width = Height × Aspect Ratio

Simplify Ratio

Divide both dimensions by greatest common divisor for clean ratio notation.

GCD simplification: 1920×1080 → 16:9

Updated: July 2026

Example Scenarios

3840 width → 2160 height. Standard UHD delivery for YouTube and streaming.

1080 width → 1920 height. Full vertical HD for mobile-first content.

3840 × 1607 active pixels with letterbox bars to 2160 total height.

FAQ

Standard HD and 4K video — 1920×1080, 3840×2160. Width divided by height equals 1.778 (16÷9).

9:16 is vertical (portrait) — TikTok, Reels, Shorts. 16:9 is horizontal landscape — TV and YouTube desktop.

Widescreen cinema scope. On 1920 wide frame, active picture height ≈ 817 pixels with letterboxing.

H.264 encoding prefers width and height divisible by 2 (macroblock alignment). Round calculated dimensions to nearest even integer.

Camera sensors may be 3:2 or 4:3 native — crop to target aspect in post or set recording format on camera.

About Layout Aspect Ratio Calculator

Compute video frame dimensions from any aspect ratio and one known side. Enter ratio (16:9, 4:3, 2.39:1, 9:16) plus width or height to get matching pixel dimensions for export, cropping, and social platform specs.