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Aspect Ratio Calculator Online Free - Width Height Ratios

Calculate aspect ratios from width and height, find missing dimensions, and explore equivalent resolutions. Includes presets for social media, film, and screen sizes.

New
Browser-based
Browser-basedRuns in your browser

No file upload is required for the standard workflow. Processing happens in the current browser session unless you choose a separate account or export feature.

How it works

Aspect Ratio Calculator computes the simplified width-to-height ratio from any pair of pixel dimensions. Enter width and height to see the aspect ratio (e.g., 16:9), decimal ratio (1.7778), and total pixel count. Use the missing dimension calculator to find proportional width or height when one value is known. Equivalent resolutions show you all standard sizes that share the same ratio, from 360p to 4K. Presets for common screen, social media, film, and print sizes speed up the workflow.

1. Upload / Input

Enter width and height in pixels in the main input fields.

2. Browser Process

View the simplified ratio, decimal value, and visual preview. Use Missing Dimension calculator to find proportional width or height.

3. Save Output

Click a preset or equivalent resolution to update the calculator.

Why Use This Tool

  • ✓Calculate simplified aspect ratio (W:H) from dimensions
  • ✓Decimal ratio and total pixel count
  • ✓Visual preview rectangle scaled to ratio
  • ✓Calculate missing width or height from one known dimension
  • ✓Equivalent resolutions (360p, 480p, 720p, 1080p, 1440p, 4K)
  • ✓Presets for Screen, Social Media, Film, and Print
  • ✓Browser-only processing

Perfect For

  • 1Verifying image dimensions before uploading to social media.
  • 2Scaling video resolutions while maintaining aspect ratio.
  • 3Setting crop dimensions for design tools.
  • 4Checking print layout proportions for A4, US Letter, etc.

Processing & Safety Note

This tool page uses the browser-based workflow described above for standard use. Account saving, AI tools, downloaders, and Temp Mail have separate handling notes.

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Trust & Security Standards

GCD-Based Simplification

Uses Greatest Common Divisor to produce the smallest integer ratio (e.g., 16:9 not 1920:1080).

Missing Dimension Calculator

Calculates proportional width or height from one known value, preserving the ratio exactly.

Equivalent Resolutions

Shows standard resolution equivalents (HD, Full HD, 4K) sharing the same ratio.

Browser-Only

All calculations run locally in JavaScript. No data is sent to a server.

FAQ

An aspect ratio is the proportional relationship between an image's width and height, expressed as W:H (e.g., 16:9). It determines how wide or tall an image appears regardless of its actual pixel dimensions.
Enter 1920 as width and 1080 as height. The tool calculates GCD and shows the simplified ratio: 16:9. The decimal ratio is 1.7778.
Enter your source dimensions in the main inputs to set the ratio, then use the 'Calculate Missing Dimension' section. Enter a known width to calculate the proportional height, or enter a known height to calculate the proportional width.
Instagram posts use 1:1 (1080x1080) or 4:5 (1080x1350). Instagram/TikTok Stories use 9:16 (1080x1920). YouTube thumbnails use 16:9 (1280x720).
16:9 is the most common widescreen aspect ratio used by HD and 4K televisions, YouTube, and modern computer monitors. At 1920x1080 (Full HD) or 3840x2160 (4K UHD).

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