Aspect Ratio Calculator

Reduce any width × height to its simplest aspect ratio — useful for screens, images and video.

How the Math Works

The Aspect Ratio Calculator simplifies a width and height into their simplest whole number ratio by finding the greatest common divisor (GCD) of the two measurements. The GCD is the largest number that divides both the width and height evenly. By dividing both dimensions by this GCD, you reduce the proportions to their most basic form. For example, a screen measuring 1920x1080 pixels has a GCD of 120, so dividing both numbers by 120 yields the simplified ratio 16:9.

Practical Applications

To use this calculator, enter your width and height measurements in any unit—pixels, inches, centimeters, or millimeters. The calculator automatically computes the GCD and divides both values to produce the simplified aspect ratio. This is essential for designing layouts, comparing screen dimensions, resizing images proportionally, or ensuring video content fits standard display formats without distortion. The calculator handles the mathematical complexity so you can focus on your creative or technical work.

Day-to-Day Use

Aspect ratios appear everywhere in daily life, from smartphone screens and computer monitors to photo frames and TV displays. Knowing the aspect ratio helps you quickly determine if your content will display correctly without black bars or cropping. When shopping for a new monitor or TV, checking the aspect ratio ensures compatibility with your devices and media. It's also useful for social media posts, where different platforms require specific image proportions, and for printing photos at the right size without stretching.

Worked example

1920 × 1080 → GCD 120 → 16:9 (1.778).

FAQ