Aspect Ratio Calculator
Enter any two values and get the rest. Solve the missing width or height for a known ratio, or detect the exact ratio from any pixel dimensions — free, instant, no sign-up.
Pick a ratio, enter one side, get the other.
Enter a width or height above.
Popular ratio calculators
Each ratio has a dedicated page with common resolutions, usage guide and a locked-ratio converter.
Social media & print size calculators
How to use this calculator
Solve missing dimension: pick a ratio (e.g. 16:9), type the width you have, and the matching height appears instantly — or type the height to get the width. Detect ratio: type both sides of an image or screen and the calculator simplifies them to the nearest standard ratio, plus the exact decimal value.
The math is simple: for ratio w:h, height = width × (h ÷ w) and width = height × (w ÷ h). Detecting a ratio divides both sides by their greatest common divisor (for whole numbers) or finds the nearest small-integer approximation.
What is aspect ratio?
Aspect ratio describes the proportional relationship between width and height, written as two numbers separated by a colon (16:9, 4:3, 1:1). It is independent of absolute size — a 1920×1080 monitor and a 480×270 video clip share the same 16:9 shape. Choosing the right ratio matters when cropping photos, exporting video, designing social posts or printing images, because every platform and print size expects a specific shape.