Ratio & Dimension Calculator

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H
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💡 Tip: Change any value, and others will update based on the current ratio.

Common Aspect Ratios

16:9

Widescreen

Standard for HDTVs, most computer monitors, and YouTube videos. Common resolutions: 1920x1080 (1080p), 3840x2160 (4K).

4:3

Traditional

Standard for old CRT TVs and iPad screens. Closer to a square shape. Common resolutions: 1024x768, 800x600.

9:16

Vertical Video

Standard for mobile videos, commonly used in TikTok, Instagram Stories, and YouTube Shorts.

How Calculation Works

Aspect Ratio describes the proportional relationship between the width and height of an image or screen. It is usually expressed as two numbers separated by a colon, e.g., 16:9.

The Formula

Width / Height = Ratio Value
New Height = New Width / (RatioWidth / RatioHeight)
New Width = New Height * (RatioWidth / RatioHeight)

Frequently Asked Questions

What is the Golden Ratio?
The Golden Ratio is approximately 1.618:1 (or about 16:10). It is considered to be aesthetically pleasing in art and design.
What is the best aspect ratio for Instagram?
Instagram supports multiple ratios: Square (1:1), Landscape (1.91:1), and Portrait (4:5). To maximize screen real estate on mobile, 4:5 (1080x1350) is recommended.
What is the 21:9 ratio?
This is the standard aspect ratio for UltraWide monitors, great for cinematic viewing (close to 2.35:1) and productivity.
Can results be decimals?
Yes. However, digital pixels must be whole numbers. We usually round the result. Our tool keeps one decimal place for reference.
How to resize an image without changing ratio?
That's the main purpose of this tool. First set the original ratio (or enter dimensions), then just change either "Width" or "Height", and the other will auto-calculate to maintain the ratio.
What is the IMAX aspect ratio?
Standard IMAX is 1.43:1, which is very tall. Digital IMAX sometimes uses 1.90:1.
Is calculation done in the cloud?
No. All calculations are done locally in your browser in real-time, which is fast and data-efficient.
What if I enter a negative number?
Dimensions cannot be negative. Our tool will automatically ignore the negative sign or treat it as an absolute value.

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