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Aspect Ratio Calculator

Calculate dimensions, simplify ratios, and find the perfect size for any format.

An aspect ratio calculator works out the missing side of a rectangle once you fix the other one. Type a width and a target ratio such as 16:9, and it returns the exact height that keeps the shape intact. It also runs in reverse: enter any width and height, and it simplifies the pair down to its lowest terms.

Calculate Dimensions

Simplified Ratio

16:9

16:9
Decimal Ratio

1.7778

width ÷ height
Total Pixels

2,073,600

2.07 megapixels
Resolution

1920 × 1080

width × height

Ratio Preview

16:9

Resolution Presets

Aspect Ratio Presets

Common Ratios

16:9HD Video, YouTube
4:3Classic TV, iPad
1:1Instagram Square
21:9Ultrawide Cinema
9:16Stories, TikTok
3:2DSLR Photos

How to Use

  1. 1.Enter width or height to see the simplified ratio
  2. 2.Click the lock icon to maintain the current ratio
  3. 3.Use presets for common formats
  4. 4.Click the copy icon to copy any value

Frequently Asked Questions

What is aspect ratio?+
Aspect ratio is the proportional relationship between an image's width and height, expressed as two numbers separated by a colon (e.g., 16:9). It describes the shape of an image or video without specifying its actual size.
What is the most common aspect ratio?+
16:9 is the most common aspect ratio for video content, TVs, monitors, and YouTube. For photography, 3:2 (used by most DSLR cameras) and 4:3 (used by many phones and older displays) are also very popular.
How do I calculate aspect ratio?+
To calculate aspect ratio, divide both the width and height by their greatest common divisor (GCD). For example, 1920÷120=16 and 1080÷120=9, giving you 16:9. Our calculator does this automatically.
What aspect ratio is 1920x1080?+
1920x1080 (Full HD or 1080p) has an aspect ratio of 16:9. This is the standard widescreen format used for HD video, most computer monitors, and TVs.
What is the best aspect ratio for Instagram?+
Instagram supports multiple aspect ratios: 1:1 (1080x1080) for square posts, 4:5 (1080x1350) for portrait feed posts, and 9:16 (1080x1920) for Stories and Reels. Square posts get equal visibility on all devices.
What is 4K resolution aspect ratio?+
4K UHD (3840x2160) has a 16:9 aspect ratio, the same as 1080p. The '4K' refers to the approximate horizontal pixel count (3840 ≈ 4000), not the aspect ratio. Cinema 4K (4096x2160) has a slightly wider 1.9:1 ratio.

Learn More

Improve your image and video workflow with these guides:

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