Aspect Ratio Calculator
Calculate scaled dimensions while preserving aspect ratio — enter original size, pick a preset (16:9, 4:3, 1:1, 21:9), and resize by width or height.
Original dimensions (defines the ratio)
Scale — edit either dimension to compute the other
New width
New height
Why you’ll love Aspect Ratio Calculator
Instant & free
No signup, no paywall, no limits — Aspect Ratio Calculator works the moment the page loads.
Completely private
Everything runs in your browser. Nothing you enter is ever uploaded or stored on a server.
Works on any device
Fully responsive and touch-friendly — use it on your phone, tablet or desktop.
Accurate & clear
Built on the real formulas, with a breakdown you can actually trust.
How to use it
Open it
No download and no login — the tool is ready right at the top of this page.
Use it
Enter your details or start interacting. Everything updates live as you go.
Get your result
Copy, download or share your result in a single tap. That’s it.
About Aspect Ratio Calculator
An Aspect Ratio Calculator helps you calculate scaled dimensions while preserving the original aspect ratio of images and media. Simply enter your original width and height, select or define an aspect ratio preset, then specify either the new width or height. The tool instantly calculates the missing dimension to maintain perfect proportions.
Whether you're working with photos, videos, designs, or web content, maintaining aspect ratio is crucial for preventing distortion. This calculator supports common presets like 16:9, 4:3, 1:1, and 21:9, while allowing custom ratios for specialized projects. Save time on manual calculations and ensure pixel-perfect scaling across all your media projects.
Popular uses
Frequently asked questions
Aspect ratio is the proportional relationship between an image's width and height, expressed as width:height (e.g., 16:9). It matters because resizing without maintaining aspect ratio causes distortion, stretching, or squishing your content. Preserving aspect ratio ensures images and videos look professional and undistorted.
Enter your original width and height dimensions, then select a preset ratio or define a custom one. Choose whether you want to resize by width or height, enter the new dimension, and the calculator will automatically compute the other dimension while maintaining the exact aspect ratio.
16:9 is standard for HD video and widescreen displays, 4:3 for traditional screens, 1:1 for square social media posts, and 21:9 for cinematic content. Choose the preset matching your target platform or medium to ensure your content displays correctly without cropping or distortion.
Aspect Ratio Calculator is 100% free — no signup, no watermarks and no usage limits. It’s one of 200+ free tools we build and give away.
It uses the standard formulas and shows its working, so you can verify every number. For big decisions, treat the result as a reliable estimate.
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