Aspect Ratio Calculator
Calculate aspect ratios from image/video dimensions, or find the correct width or height for any ratio like 16:9, 4:3, 1:1. Includes common presets.
When to Use
Use when resizing images or videos for social media, calculating canvas dimensions, or preparing assets for specific platform requirements.
How to Use Aspect Ratio Calculator
- Mode 1 — Dimensions to Ratio: Enter width and height in pixels. The simplified ratio is shown instantly.
- Mode 2 — Ratio to Dimensions: Enter a ratio (e.g. 16:9) and one dimension to calculate the other.
- Use the common ratio presets (16:9, 4:3, 1:1, 9:16, etc.) for quick selection.
- The decimal form of the ratio is shown alongside for precision work.
- Copy the ratio or dimensions for use in your video editor or design tool.
Examples
1920x1080 ratio
Input: Width: 1920, Height: 1080
Output: Aspect ratio: 16:9 (1.7778)
16:9 at 720px wide
Input: Ratio: 16:9, Width: 720
Output: Height: 405 px
Frequently Asked Questions
What is an aspect ratio?
An aspect ratio describes the proportional relationship between a rectangle's width and height. For example, 16:9 means for every 16 units wide, the image is 9 units tall.
What aspect ratio should I use for YouTube?
YouTube videos should use 16:9 (widescreen). The recommended resolution is 1920×1080 (Full HD) or 3840×2160 (4K).
What is the best aspect ratio for Instagram?
Instagram supports 1:1 (square), 4:5 (portrait), and 1.91:1 (landscape). The 4:5 portrait format occupies the most screen space in the feed.
Why does my image look stretched when I resize it?
Stretching occurs when you change one dimension without maintaining the aspect ratio. Use this calculator to find the correct second dimension so the image is never distorted.