Aspect Ratio Calculator
Calculate and maintain aspect ratios for images, videos, and screens. Enter one dimension and get the other — perfect for resizing without distortion.
Enter one dimension and the other will be calculated automatically:
All calculations run entirely in your browser.
An aspect ratio is the proportional relationship between an image's width and height, expressed as two numbers separated by a colon (e.g., 16:9). Getting it right is essential — stretch an image to fit a different ratio and it looks distorted, amateurish, and unprofessional. Our free Aspect Ratio Calculator makes it effortless. Choose from common presets (16:9 widescreen, 4:3 standard, 1:1 square, 9:16 vertical video, and more), enter either width or height, and instantly get the matching dimension that preserves the exact proportions. Or enter both dimensions in custom mode to find the simplified ratio. A visual preview shows the aspect ratio as a scaled rectangle, and a complete reference table of common screen and social media resolutions helps you design for the right output format from the start.
How to Use
- Choose a mode — Select Preset Ratio to pick from common formats (16:9, 4:3, 1:1, etc.) or Custom W×H to calculate the ratio from your dimensions.
- Enter dimensions — In preset mode, enter either width or height and the other resolves automatically. In custom mode, enter both to see the simplified ratio.
- Read the result — View the calculated dimensions, simplified ratio, decimal value, and percentage. A visual preview shows the proportion to scale.
- Reference common resolutions — The table shows standard screen sizes, social media image dimensions, and paper formats for quick reference.
Key Features
- 9 Presets + Custom
16:9, 4:3, 3:2, 1:1, 21:9, 9:16, and more. Custom mode for any dimensions.
- Auto-Calculate Missing Dimension
Enter width to get the proportional height, or vice versa. The math is done instantly.
- Visual Preview
A scaled rectangle shows the exact proportion — making it easy to visualize the aspect ratio.
- Resolution Reference
15 common display resolutions with aspect ratios — HD, 4K, 8K, social media, print.