Free Aspect Ratio Calculator
Calculate proportional image/video dimensions and aspect ratios instantly. No registration, runs 100% locally in your browser.
1. Base Dimensions (Calculates Ratio)
2. Target Proportional Scaling
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How Aspect Ratio Calculator Works
Enter your starting width and height to calculate the base aspect ratio.
Lock the aspect ratio, and enter a new target width to get the auto-calculated height (or vice versa).
Choose from standard preset ratios (16:9, 1:1, 4:3, 9:16) to scale dimensions instantly.
Frequently Asked Questions
We calculate the Greatest Common Divisor (GCD) using the Euclidean algorithm to simplify width and height to their lowest integer ratio.
Yes! Check the "Lock Ratio" switch and when you modify width, height updates proportionally (and vice versa).
Yes, we include common modern presets like Instagram Square (1:1), Portrait (4:5), YouTube Video (16:9), and Mobile Stories (9:16).
Yes, it works smoothly across all devices, screens, and orientations.