Free Aspect Ratio Tools
Enter a width and height to find its ratio, or enter a ratio plus one side to get the exact missing dimension. Free, instant, and computed entirely in your browser.
Open the CalculatorAspect Ratio Tools
Aspect Ratio Calculator
Find the ratio of any width and height, or work out the missing dimension from a ratio.
Use the ToolAspect Ratio Comparator
Compare two aspect ratios to see if they match, and by how much they differ.
Use the ToolCrop Size Calculator
Find the largest crop of a target ratio that fits inside your original image.
Use the ToolPopular Aspect Ratios
16:9
The widescreen standard: resolutions, uses and exact dimensions at 16:9.
9:16
The vertical standard: exact dimensions for Stories, Reels, Shorts and TikTok.
4:3
The classic shape of SD television, iPads and medium-format photos.
3:2
The 35 mm film shape used by DSLRs and 4×6 prints.
21:9
Ultrawide monitors: exact dimensions of 3440×1440, 2560×1080 and more.
1:1
The square: Instagram posts, avatars, album art and OG-friendly crops.
5:4
The 8×10 print shape and the SXGA monitor standard.
2:3
Portrait photography's vertical shape: the 2:3 twin of 3:2.
Sizes by Platform & Use
Aspect Ratio for Images
Pick the right image ratio for web, social and print - and size it exactly.
Aspect Ratio for Video
16:9, 9:16 or 2.39:1? Match your video's shape to where it will play.
YouTube Aspect Ratio
YouTube's 16:9 player, 9:16 Shorts and exact thumbnail dimensions.
Instagram Aspect Ratio
Feed posts, Stories and Reels: every Instagram ratio and exact pixel size.
TikTok Aspect Ratio
TikTok's 9:16 full-screen format and the safe zones the UI covers.
Aspect Ratio for Print
Match photos to paper: 4×6, 8×10, A4 and how DPI turns pixels into inches.
Browse by Category
Aspect Ratio Guides
What Is Aspect Ratio
The definition of aspect ratio, how to read W:H, and why it matters.
Common Aspect Ratios
Reference table: every common ratio, its decimal value and where it is used.
How to Change Aspect Ratio
Crop, pad or reframe: the three ways to change a ratio without ruining the image.
Aspect Ratio vs Resolution
Shape versus pixel count - how the two differ and why both matter.