Aspect Ratio Calculator
Calculate aspect ratios instantly with our free Aspect Ratio Calculator. Enter any width and height to get the simplified ratio (e.g., 1920x1080 = 16:9), then use the resize calculator to find new dimensions that maintain the same proportions. Includes common presets for video (16:9, 4:3, 21:9), social media (1:1, 9:16), and photography. Essential for video editors scaling footage, designers resizing images, and developers building responsive layouts. Uses GCD algorithm for precise ratio simplification. Runs entirely in your browser with no data collection.
Aspect Ratio
Resize Calculator
Enter a new width or height to calculate the other dimension while maintaining the 16:9 ratio.
How to Use
- 1
Enter Dimensions
Type the width and height of your image, video, or screen in the input fields.
- 2
View Ratio
The simplified aspect ratio (e.g., 16:9) and decimal value are displayed instantly.
- 3
Use Presets
Click a common preset (16:9, 4:3, 1:1, etc.) to quickly set standard dimensions.
- 4
Resize Proportionally
Enter a new width or height in the resize section to calculate the other dimension while keeping the ratio.
Examples by Niche
1920x1080 simplifies to 16:9 — the standard widescreen ratio for YouTube, streaming, and most monitors.
1080x1080 = 1:1 square for Instagram posts; 1080x1920 = 9:16 vertical for Stories and Reels.
6000x4000 simplifies to 3:2 — the classic DSLR aspect ratio used by most Canon and Nikon cameras.
Frequently Asked Questions
How is the aspect ratio calculated?
The calculator uses the Greatest Common Divisor (GCD) algorithm to simplify your width and height into the smallest equivalent ratio. For example, 1920x1080 shares a GCD of 120, yielding 16:9.
Can I resize while keeping the aspect ratio?
Yes — enter a new width or height in the resize section and the calculator automatically computes the other dimension to maintain the exact aspect ratio. This prevents image distortion.
What common aspect ratios are included?
Presets include 16:9 (widescreen), 4:3 (standard), 21:9 (ultrawide), 1:1 (square/Instagram), and 9:16 (vertical/TikTok/Reels). Click any preset to auto-fill the dimensions.
What aspect ratio should I use for YouTube videos?
Standard YouTube videos use 16:9 (1920x1080 for 1080p, 3840x2160 for 4K). YouTube Shorts use 9:16 (1080x1920). Uploading a video with a non-standard ratio results in black bars (letterboxing or pillarboxing), so matching the correct ratio before export avoids wasted screen space.
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