What this tool helps you find
Enter the original width and height. To resize proportionally, provide either a new width or a new height and leave the other optional field empty.
Formula
Aspect ratio = width ÷ greatest common divisor(width, height).
Worked example
A 1920 × 1080 display simplifies to 16:9.
Common mistake
Enter width before height and use the same unit for both dimensions. Entering both resize fields can make the intended target unclear.
When to use it
Keep a photo, video, presentation, or screen layout in proportion when changing its dimensions.
Questions and answers
What does aspect ratio mean?
It describes the proportional relationship between width and height.
Will resizing keep the image proportional?
Yes. Enter either a new width or height and the other dimension is calculated from the original ratio.