Aspect Ratio Calculator
Calculate missing width or height from a known aspect ratio, or simplify any dimensions into a clean width-to-height ratio. Great for monitors, video exports, mockups, and social media graphics.
Calculated Height
1080.00 px
Ratio: 16:9
Exact Formula
height = width × 9 ÷ 16
Best for videos, images, CSS layouts, ad creatives, and screen mockups.
Aspect Ratio Preview
Visualize how the current ratio will look on a screen, image, or canvas.
Reference Ratios
YouTube videos, TVs, laptops, and most modern monitors.
Presentations, older screens, and some tablet layouts.
Ultrawide monitors, cinematic editing, and immersive gaming.
Instagram posts, avatars, and square thumbnails.
Photography, prints, and DSLR image framing.
Phone video, TikTok, Reels, and Stories.
Common Aspect Ratios
| Ratio | Shape | Typical Use Cases |
|---|---|---|
| 16:9 | Landscape | YouTube videos, TVs, laptops, and most modern monitors. |
| 4:3 | Landscape | Presentations, older screens, and some tablet layouts. |
| 21:9 | Landscape | Ultrawide monitors, cinematic editing, and immersive gaming. |
| 1:1 | Square | Instagram posts, avatars, and square thumbnails. |
| 3:2 | Landscape | Photography, prints, and DSLR image framing. |
| 9:16 | Portrait | Phone video, TikTok, Reels, and Stories. |
How to Use
- Choose Calculate Missing Dimension if you know either the width or height and want the other value.
- Select a common ratio like 16:9, 4:3, 21:9, 1:1, 3:2, 9:16, or enter your own custom ratio.
- Use the resolution presets to quickly load common screen sizes such as 1920×1080 or 3840×2160.
- Switch to Find Aspect Ratio mode to simplify any width and height into its lowest ratio.
Frequently Asked Questions
What is an aspect ratio?
An aspect ratio describes the proportional relationship between width and height. A 16:9 ratio means the width is 16 units for every 9 units of height, regardless of the actual pixel size.
How do I calculate a missing dimension?
Multiply the known dimension by the opposite side of the ratio, then divide by the known side. For example, for a 16:9 image with a width of 1920, height = 1920 × 9 ÷ 16 = 1080.
What aspect ratio is best for social media?
It depends on the platform and format. 1:1 works well for square posts, 9:16 is best for Stories and Reels, and 16:9 is common for YouTube and landscape video.
Why do aspect ratios matter for screens and images?
Using the correct aspect ratio prevents stretching, black bars, awkward crops, and blurry scaling. It helps designs, videos, and photos display as intended on different devices.