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How to Use
- 1To find the ratio: enter width and height in pixels and click Calculate Ratio.
- 2To find a dimension: switch to the "Dimension from Ratio" tab.
- 3Select a preset ratio (16:9, 4:3, etc.) or enter a custom ratio.
- 4Enter the known dimension and select whether it is the width or height.
- 5Click Calculate to get the missing dimension.
About Aspect Ratio Calculator
The Aspect Ratio Calculator has two modes: calculate the simplified ratio from any two dimensions (e.g. 1920×1080 → 16:9), or calculate a missing dimension when you know the ratio and one side.
Essential for video creators, graphic designers, web developers, and photographers working with responsive images, video exports, thumbnails, and social media formats.
Frequently Asked Questions
What is an aspect ratio?
An aspect ratio is the proportional relationship between width and height, expressed as W:H (e.g. 16:9). It describes shape regardless of actual size.
What ratio is 1920x1080?
1920×1080 is a 16:9 aspect ratio — the standard for HD and Full HD video, YouTube thumbnails, and most modern monitors.
How does the ratio simplification work?
The tool divides both dimensions by their greatest common divisor (GCD) to produce the simplest integer ratio.
Which ratio should I use for Instagram?
Instagram supports 1:1 (square), 4:5 (portrait), and 1.91:1 (landscape). Stories and Reels use 9:16.