Calculate aspect ratios for any size
Find missing dimensions for images, videos, and UI elements based on standard or custom aspect ratios.
About This Tool
Aspect Ratio Calculator is essential for designers and developers who need to maintain correct proportions when resizing images, videos, or responsive UI containers.
Key Features
Common presets: 16:9, 4:3, 1:1, 3:2, 9:16
Custom ratio input
Solve for width or height
Pixel-perfect results
Instant real-time calculation
How to Use This Tool
- Select a preset ratio (e.g. 16:9) or enter a custom ratio.
- Enter either the width or height.
- The missing dimension is calculated instantly.
Why Use This Tool
- Prevents distorted images when resizing for different screens.
- Covers common video, photo, and social media aspect ratios.
- Works completely offline in the browser.
Pro Tips
- Use 16:9 for YouTube thumbnails and video embeds
- Use 1:1 for Instagram post images
- Use 9:16 for mobile stories and TikTok-style vertical video
Frequently Asked Questions
What is aspect ratio?
Aspect ratio is the proportional relationship between width and height, e.g. 16:9 means for every 16 units of width, there are 9 units of height.
Can I enter a custom ratio?
Yes, you can enter any W:H ratio in the custom ratio fields.
What units are used?
The tool is unit-agnostic. You can use pixels, centimetres, inches — just be consistent.