Aspect Ratio Calculator & Dimension Resizer
Free in-browser Aspect Ratio Calculator and dimension scaler. Instantly calculate simplified aspect ratios (16:9, 4:3, 1:1, 9:16, 21:9), compute decimal ratios, generate CSS aspect-ratio properties, and calculate new width or height while keeping exact proportions. Includes standard display and social media presets.
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How to Calculate Aspect Ratio in 3 Steps
Enter Original Dimensions
Input your image, video, or screen width and height in pixels.
Inspect Ratio & CSS
View the simplified fraction (e.g. 16:9), decimal ratio, and copy CSS aspect-ratio code.
Scale to New Dimensions
Enter a new target width or height to automatically calculate scaled dimensions.
Frequently Asked Questions
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