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4:3 aspect ratio calculator

Calculate 4:3 aspect ratio dimensions for classic monitors, iPads and photos. Enter width or height for instant calculation.

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Pixel dimensions (px)

px
px
Proportional Preview

Simplified: • Decimal:

CSS Snippet


            

Common Aspect Ratio Guide

Aspect Ratio Decimal Common Uses Standard Resolutions
16:9 1.778 YouTube, widescreen displays, TV broadcasting, desktop monitors 1920×1080 (FHD), 3840×2160 (4K), 1280×720 (HD)
9:16 0.563 TikTok, Instagram Reels, YouTube Shorts, smartphone stories 1080×1920, 720×1280
4:3 1.333 Classic TV monitors, iPad screens, point-and-shoot cameras 1024×768, 1600×1200, 2048×1536
1:1 1.000 Square social media feeds (Instagram, LinkedIn), avatars, profile photos 1080×1080, 800×800, 500×500
21:9 2.333 Ultrawide gaming monitors, theatrical film releases, anamorphic video 2560×1080, 3440×1440, 5120×2160
3:2 1.500 35mm film, DSLR & mirrorless photography, Microsoft Surface laptops 6000×4000, 3000×2000

About this tool

Calculate 4:3 aspect ratio dimensions for iPad displays, classic monitors, and camera sensors. Enter your target width or height to see the proportional size.

How to use it

  1. 1 Choose a standard ratio preset (16:9, 9:16, 4:3, 1:1, 21:9) or type custom ratio values.
  2. 2 Enter either the Width or Height in pixels; the other dimension calculates automatically.
  3. 3 Click any common resolution button (1080p, 4K, 720p, TikTok) for instant dimensions.
  4. 4 Copy the CSS aspect-ratio snippet or pixel dimensions to use in your project.

Questions

What is the formula to calculate aspect ratio?

Aspect ratio is the proportional relationship between width and height: Aspect Ratio = Width / Height. To calculate height from width: Height = Width × (Ratio Height / Ratio Width). To calculate width from height: Width = Height × (Ratio Width / Ratio Height).

What is the best aspect ratio for YouTube, TikTok and Instagram?

YouTube horizontal videos and standard desktop screens use 16:9 (1920×1080). TikTok, Instagram Reels, and YouTube Shorts use 9:16 vertical video (1080×1920). Instagram feed posts typically use 1:1 square (1080×1080) or 4:5 portrait (1080×1350).

How do I use the CSS aspect-ratio property?

Modern CSS supports the native aspect-ratio property, for example: aspect-ratio: 16 / 9; or aspect-ratio: 1 / 1;. This maintains element proportions responsively without needing older padding-bottom percentage hacks.

How do I find the aspect ratio of an existing image?

Divide the image width by the greatest common divisor (GCD) of the width and height, and do the same for the height. For example, 1920 × 1080 divided by GCD 120 yields exactly 16:9.

Is my data uploaded?

No. This tool runs in your browser, so your text and files never reach our server.

Is this tool free?

Yes. It’s free to use with no sign-up and no limits for normal use.