What is aspect ratio — 1:1, 4:5, 16:9

Aspect ratio is width divided by height. 1:1 is a square. 4:5 is taller than it is wide. 16:9 is widescreen. Platforms crop whatever does not match, so it is better to crop yourself.

The crop tool in ToolsHelper locks common ratios and still lets you drag the frame. Original keeps the photo’s own proportion while you trim edges.

Aspect ratio is width divided by height. 16/9 is about 1.78, 4/3 is about 1.33, and 1/1 is a square. Two files with the same ratio can have very different pixel counts. Fitting a 4:3 photo into a 16:9 frame either crops, adds bars, or stretches. This page defines the ratio. The crop tool is where you choose which pixels survive.