Aspect Ratio Calculator
Calculate an image, video, or screen aspect ratio and resize dimensions while preserving proportions.
Enter the original width in pixels, inches, centimeters, or any consistent unit.
Enter the original height in the same unit as width.
Choose which target dimension you know.
Optional new width. The calculator will preserve the original aspect ratio.
Optional new height. Use when resizing by target height.
Status: initial
Results
Awaiting calculation
Introduction
The Aspect Ratio Calculator reduces width and height to a clean ratio and calculates proportional resize dimensions for images, videos, screens, and layouts.
Reduce width:height by the greatest common divisor. To resize proportionally, multiply the known target dimension by the original opposite dimension and divide by the original matching dimension.
Formula and method guide
Reduce ratio
Aspect ratio = width:height reduced by GCD
Use this to convert pixel dimensions such as 1920 x 1080 into 16:9.
Find target height
Target height = target width x original height / original width
Use this when resizing to a specific width without stretching.
Find target width
Target width = target height x original width / original height
Use this when resizing to a specific height without stretching.
Variables
The horizontal dimension of the image, video, screen, or layout.
The vertical dimension using the same unit as width.
The reduced width-to-height relationship.
Width divided by height, often written as something like 1.7778:1.
The resized dimensions that preserve the same proportion.