Aspect Ratio Calculator – Calculate & Resize Dimensions

Presets:

Input Original Dimensions

Original Width (px)

Original Height (px)

Optional: Resize while preserving ratio

New Width (px)

New Height (px)

Copyable Aspect Ratio Snippets

CSS / Tailwind / HTML

CSS Property

aspect-ratio: 16 / 9;

Tailwind CSS Utility

aspect-video

HTML Attribute

<iframe width="560" height="315" style="aspect-ratio: 16 / 9;"></iframe>

Visual Aspect Preview

16:9 Widescreen

Scale: Relative Proportions 1920 × 1080

Calculated Results

Aspect Ratio

16:9

Decimal Ratio

1.7778

Orientation

Landscape

Standard Preset

16:9 Widescreen

Resized Result

1920 × 1080 px

Proportionally scaled based on aspect ratio

Equivalent Common Resolutions

Scales preserving the exact calculated ratio

How the Aspect Ratio Calculator Works

An aspect ratio represents the proportional relationship between an image or display screen’s width and height. Regardless of the actual physical size or pixel count, the aspect ratio remains constant.

Mathematical Formula

The simplified ratio is calculated by dividing both width and height by their Greatest Common Divisor (GCD):

GCD = gcd(width, height)
Ratio Width  = width / GCD
Ratio Height = height / GCD

To compute a missing dimension while preserving the aspect ratio:

New Height = (New Width × Original Height) / Original Width
New Width  = (New Height × Original Width) / Original Height

Common Aspect Ratios & Use Cases Reference Table

Aspect Ratio	Decimal	Common Resolutions	Primary Use Cases
16:9	1.7778	1280×720, 1920×1080, 3840×2160	YouTube, HDTV, PC Monitors, Video Games
9:16	0.5625	720×1280, 1080×1920, 1440×2560	YouTube Shorts, Instagram Reels, TikTok, Stories
1:1	1.0000	1080×1080, 2048×2048	Instagram Posts, Profile Avatars, Product Cards
4:3	1.3333	1024×768, 1600×1200, 2048×1536	Legacy Displays, iPads, Photography, Micro Four Thirds
3:2	1.5000	3000×2000, 2160×1440	DSLR & Mirrorless Cameras, Surface Laptops
21:9	2.3333	2560×1080, 3440×1440, 5120×2160	Ultrawide Gaming Monitors, Cinematic Film

Frequently Asked Questions

Common questions about this tool.

How do you calculate aspect ratio from width and height? ▼

Divide both the width and height by their Greatest Common Divisor (GCD). For instance, for 1920 × 1080, the GCD is 120. Dividing 1920 by 120 gives 16, and dividing 1080 by 120 gives 9, resulting in a 16:9 ratio.

What is the standard aspect ratio for video? ▼

The universal widescreen standard for video displays, YouTube, and television is 16:9 (such as 1920×1080 or 3840×2160). For vertical mobile content like Shorts, Reels, and TikTok, 9:16 (1080×1920) is standard.

How do I resize an image without distorting it? ▼

To preserve the original aspect ratio when resizing, calculate the new height as (New Width × Original Height) / Original Width, or new width as (New Height × Original Width) / Original Height.