Aspect ratio decides the shape of every image, video and screen you see. Get it wrong and your content looks stretched or cropped. This guide explains aspect ratios in plain English and shows how to resize correctly.
What is an aspect ratio?
An aspect ratio is the relationship between width and height, written as width:height. A 16:9 ratio means 16 units wide for every 9 units tall. You can find the ratio of any size with our Aspect Ratio Calculator.
Common aspect ratios
- 16:9 — widescreen video, YouTube, modern TVs
- 4:3 — older displays and some photos
- 1:1 — square, popular on social media
- 9:16 — vertical video, Stories and Reels
How to resize without distortion
To avoid stretching, always scale width and height by the same proportion. Our aspect ratio tool can calculate the matching height for any new width. To actually change an image’s dimensions, use the Image Resizer, which keeps the aspect ratio locked by default.
Frequently asked questions
What does keeping aspect ratio mean? It means resizing so the shape stays the same and the image does not look squashed or stretched.
Which aspect ratio should I use? Use 16:9 for most video, 1:1 or 4:5 for social posts, and 9:16 for vertical/Story content.