Aspect Ratio Calculator
Calculate aspect ratios and find optimal resolutions
Common Ratios
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What is this tool?
Aspect ratio calculator computes the width-to-height proportion of an image, video, or screen. Common ratios include 16:9 (widescreen), 4:3 (standard), 1:1 (square), and 21:9 (ultrawide). It helps you resize media while maintaining proportions, convert between ratios, and calculate dimensions for design and video production.
How to use
- 1
Enter known values
Input width and/or height and the desired aspect ratio.
- 2
Calculate
The calculator computes the missing dimension automatically.
- 3
View results
Review the output.
Frequently Asked Questions
What is the aspect ratio of a full HD screen?
Full HD (1920×1080) has a 16:9 aspect ratio. This is the standard for modern TVs, monitors, and video content. 4K UHD (3840×2160) also uses 16:9.
How to maintain aspect ratio when resizing?
New height equals new width divided by ratio.
What aspect ratio does YouTube recommend?
YouTube recommends 16:9 (1920×1080) for standard videos. For YouTube Shorts, use 9:16 (1080×1920). The platform also supports cinematic 21:9 and square 1:1 formats, but 16:9 provides the best viewing experience across all devices and avoids letterboxing.
How do I calculate an aspect ratio?
Divide the width by the height and reduce the fraction. A 1920×1080 image is 1920:1080, and dividing both by their greatest common divisor (120) gives 16:9.