Aspect Ratio Calculator
Calculate the simplified aspect ratio of a width and height, and scale to any target width.
Enter your values to calculate your result.
Formula
Simplified Ratio = Width ÷ GCD : Height ÷ GCD Calculated Height = Target Width × (Height ÷ Width)
The greatest common divisor (GCD) of the width and height is used to reduce both to the smallest whole-number ratio that represents the same proportions (e.g. 1920×1080 simplifies to 16:9). If a target width is entered, the matching height that preserves the same proportions is also calculated.
Example
1920×1080 simplifies to a 16:9 ratio (decimal 1.7778). Scaling to a target width of 1280 gives a calculated height of 720.
Frequently Asked Questions
What is the GCD and why does it matter here?
The greatest common divisor is the largest number that divides both the width and height evenly. Dividing both by it gives the simplest equivalent ratio, like reducing a fraction.