How do I calculate an aspect ratio?

Enter the width and height in pixels. The tool instantly shows the simplified ratio (e.g. 16:9), the decimal value, the inverse ratio, and the closest common format (Widescreen HD, Square, Portrait, etc.).

How is the simplified ratio calculated?

The tool divides both width and height by their Greatest Common Divisor (GCD), reducing them to the smallest whole-number ratio. For example, 1920×1080 simplifies to 16:9.

Is the aspect ratio calculator free?

Yes, completely free. All calculations run entirely in your browser — no data is sent to any server, and no signup is required.

Aspect Ratio Calculator

Calculate the aspect ratio of any resolution instantly. Enter width and height to get the simplified ratio (16:9, 4:3, 1:1…), decimal value, and closest common format. Free, runs in your browser.

Presets:

Width (px)

Height (px)

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How to Use the Aspect Ratio Calculator

Enter the width and height in pixels.
The simplified ratio, decimal value, and closest common format appear instantly.
Use the preset buttons to quickly load common resolutions (1920×1080, 4K, etc.).
Click "Copy" next to any row to copy the value.

Common Aspect Ratios

16:9 — Widescreen HD (1920×1080, 2560×1440, 3840×2160)
4:3 — Standard definition TV and older monitors (1024×768)
1:1 — Square format, Instagram posts
21:9 — Ultrawide monitors (2560×1080, 3440×1440)
9:16 — Portrait / mobile video (Stories, Reels, TikTok)