While looking for a new computer monitor or browsing for a movie on IMDb, you may have come across the term “aspect ratio.” The word is broadly used in the video and photography fields. Aspect ratio is a very simple mathematical concept.
Aspect ratio definition in video and photography
Aspect ratio is the ratio of the width and height of a four-sided object such as a TV screen, computer monitor or photo. Like any mathematical ratio, the aspect ratio of a rectangle does not refer to its physical dimensions, but rather to how the width and length of an object relate to each other.
A complete square will have an aspect ratio of 1:1 because the width of the square must equal its length. Aspect ratios can be expressed as whole numbers (such as 3:2) or in decimal places (such as 1.5:1).
By using the aspect ratio, you can calculate the height of an object via its width (and vice versa). The 16:9 aspect ratio is probably the most popular, which is often read as “sixteen by nine”, with the first number refers to the width (16) and the second to height (9).
The aspect ratio relates to the shape of the frame in film production. 1.85:1 (widescreen) and 2.39:1 are two of the most popular aspect ratios you’ll see at the movies. When you view most movies, you’ll notice black bars along the top and bottom of the screen.
The TV has settled on a 16:9 ratio for most broadcast content, although displays exist in all sorts of aspect ratios. The ultra-fast monitors that are preferred by many gamers may come with an aspect ratio of 2.37:1 (commonly marketed as “21:9”), with so-called “32:9” ultra-high-resolution monitors now available from a few manufacturers.
Using aspect ratio calculator
If you want to fit a specific piece of content to a specific device — say, a wallpaper on a smartphone — an aspect ratio calculator like this one by Andrew Hedges can help.
With this tool, you can calculate the height or width based on the aspect ratio, or even work in reverse to calculate the aspect ratio in a rectangle based on physical dimensions.
So, for example, to calculate the height based on width and aspect ratio, enter the aspect ratio in the W1 and H1 boxes, then add the physical width in the W2 box. The calculator will reveal the relative height in the H2 field.
You can find the aspect ratio of any rectangle by entering the physical dimensions in the W1 and H1 boxes and the ratio will be displayed.
Maintain aspect ratio at all costs
When it comes to content like photos and videos, deviating from the aspect ratio when resizing will cause an image to appear stretched or compressed. For best results, always keep the aspect ratio you’re working with to avoid unsightly warping.
Disney famously made this mistake when it decided to extend classic episodes of The Simpsons at Disney+ to accommodate modern 16:9 displays. Thankfully, you can still watch The Simpsons in a 4:3 aspect ratio with mods.