AspectCalc

AspectCalc is a small-sized and portable tool you can use to determine the correct aspect ratio when you're looking to resize images or videos using tools that aren't equipped with the feature to automatically maintain the aspect ratio when changing just the width or height.

Since the app's wrapped in a portable package, you can extract its files to a custom location on the disk or to a USB flash drive to effortlessly run AspectCalc on any computer. It keeps all its files in a single folder, so no traces will be left behind on the computer after removing the directory. Also, it doesn't change system registry settings.

The interface of the tool is made from a dark window with multi-colored text, which may seem confusing at first sight. However, after a bit of examination, you'll probably come to the conclusion that the tool's very easy to use. It's possible to apply predefined or custom values.

When it comes to presets, you can pick the width (X1) in the yellow column (ranging from 200 to 1920 pixels) and the height (Y1) in the blue column (ranging from 180 to 1080 pixels) to automatically place the numerical values in the yellow and blue box, respectively. In this case, you can find out the ratio multiplier, which is instantly calculated.

Otherwise, you can choose the aspect ratio that you wish to obtain (red column, 5:4, 4:3, 3:2, 16:10, 16:9) to find out the width, height and ratio multiplier. Either the width or height can be edited in the yellow (X1), blue (Y1) or green boxes (X2, Y2) to determine the missing values by taking into account the ratio multiplier.

All things considered, AspectCalc is a simplistic, yet practical tool for helping you decide what aspect ratio to apply when changing the width and height of your pictures and videos.