Calculator for Resizing an Image While Preserving its Aspect Ratio

This is a simple calculator for calculating the dimensions of a resized image while preserving the aspect ratio.

Resize Image Aspect Ratio Calculator Header Image
Last Updated:
Filed Under: Tools & Calculators

I MAY get commissions for purchases made through links in this post.

The Calculator

How to Use It

  1. Simply put in the width and height of the original image.
  2. Then enter a value into either the target width or target height. The other value will be calculated automatically. And you can tweak the numbers and have it update automatically.

What It Does

Any image editing software or app worth its salt will of course give you the option of preserving the aspect ratio of an image when resizing it. Otherwise, you’d constantly end up with images that are squashed or stretched in one dimension. So if you’re just resizing an image in an app, you probably don’t need to calculate the pixel dimensions manually.

But there are also times that I need to calculate the pixel dimensions of a resized image without running it through an image editing app. A common situation where I run into this need is when adjusting html code for resized images. It’s not technically resizing the image–it’s changing the display size for it.

So I’m posting this here mainly for my own use. But if someone else happens to find it useful, great!

This rounds to the nearest whole number, because I find that the most useful when working with pixel dimensions. That said, it’s agnostic on the type of measurements–eg. pixels or inches or miles–so long as they’re the same type for all fields.

David Coleman / Photographer

David Coleman

I'm a professional freelance travel photographer based in Washington DC. Seven continents, up mountains, underwater, and a bunch of places in between. My images have appeared in numerous publications, and you can check out some of my travel photography here. More »

Leave a Comment