Aspect Ratio Calculator

Resolution & Aspect Ratio Conversion Tool

Easily convert between aspect ratios and resolutions. Supports common ratios like 16:9, 4:3, and 21:9. Instantly calculate resolutions for video editing, image resizing, and web design.

How to Use

Calculate aspect ratios in just 3 simple steps:

Step 1: Select Calculation Mode
Choose "Calculate aspect ratio from resolution" or "Calculate resolution from aspect ratio".
Step 2: Enter Values
Input width and height, or select an aspect ratio and specify one dimension. Common ratios are available as presets.
Step 3: View Results
Results are displayed in real-time. The most simplified aspect ratio notation using GCD is automatically calculated.

Privacy Protection: All calculations are performed in your browser. No data is transmitted.

Aspect Ratio Calculator Tool

Calculation Mode

Width (px)

Height (px)

Results

Use Cases

Aspect Ratio Calculator is useful in various scenarios:

1. Determining Frame Size for Video Editing

For uploading 16:9 videos to YouTube, enter "16:9, width 1920" to automatically calculate height "1080". Instantly confirm Full HD (1920x1080) is optimal.

2. Maintaining Ratio When Resizing Images

For an original image of 4032x3024, when reducing width to 1200px while maintaining 4:3 aspect ratio, height is automatically calculated as "900px". Prevents image distortion.

3. Responsive Design for Web

If design comp is 1920x1080 (16:9), mobile (375px width) height calculates to "211px". Enables proper height settings for responsive design.

4. Optimal Image Sizes for Social Media

Instagram feed posts recommend 1:1 (square): width 1080px = height 1080px. Stories use 9:16 (vertical): width 1080px = height 1920px.

5. Print Size Calculations

L-size photo (127x89mm) has aspect ratio of approximately "1.43:1" (10:7). Calculate exact ratios and preview digital images beforehand.

6. Display Resolution Verification

For a 2560x1440 monitor, aspect ratio confirms as "16:9" (simplified). Useful reference when choosing monitors with same ratio during replacement.

What is Aspect Ratio?

Aspect ratio represents the proportional relationship between width and height of images, videos, or displays. Also known as screen ratio.

Aspect Ratio Notation

Aspect ratios are expressed as "width:height". Example: 16:9 means "16 units wide for every 9 units tall". A resolution of 1920x1080 has a 16:9 aspect ratio.

16:9 (Widescreen)

The modern standard aspect ratio. HD (1280x720), Full HD (1920x1080), and 4K (3840x2160) are all 16:9. Widely used for TVs, PC monitors, and YouTube videos.

4:3 (Standard)

Standard ratio from analog TV era. Used in old monitors (1024x768, 1600x1200) and early digital cameras. Now seen in retro games and some presentation materials.

21:9 (Ultrawide)

Horizontal ratio close to cinema screens. Used in ultrawide monitors (2560x1080, 3440x1440). Ideal for gaming, video editing, and multitasking.

1:1 (Square)

Equal width and height ratio. Used for Instagram posts (1080x1080), profile pictures, and CD covers. Visually balanced and optimal for mobile display.

9:16 (Vertical)

Ratio of smartphone held vertically. Standard for Instagram Stories (1080x1920), TikTok, and YouTube Shorts. Important for mobile-first content.

Importance of Aspect Ratio

Incorrect aspect ratios cause images and videos to stretch or compress, creating distortion. Especially for social media posts, video editing, and web design, matching target platform's recommended ratio is crucial.

Simplification Using GCD

1920x1080 simplifies to 16:9 when divided by GCD of 120. This tool automatically calculates the most concise ratio notation, making it easier to understand essential proportions.

Benefits of This Tool

Aspect Ratio Calculator offers these advantages:

Bidirectional Conversion: Convert both from resolution to aspect ratio and from aspect ratio to resolution. Flexibly calculate needed values.
8 Preset Ratios: One-click selection of common aspect ratios: 16:9, 4:3, 21:9, 1:1, 9:16, 3:2, 5:4, 2.35:1. Reduces manual input effort.
Automatic Simplified Display: Uses GCD to automatically calculate most concise aspect ratio notation. Understand essential ratios: 1920x1080 → 16:9, 3840x2160 → 16:9.
Real-Time Calculation: Results display instantly as you type, showing total pixels, megapixels, and decimal notation immediately. Dramatically improves work efficiency.
Completely Free & No Installation: Use instantly in your browser with no app installation or user registration required. All features are completely free.

Frequently Asked Questions

What is 4K resolution in 16:9 aspect ratio?

Standard 4K resolution is 3840x2160. This has a 16:9 aspect ratio. It's exactly 2x the width and height of Full HD (1920x1080), making total pixels 4x larger (approximately 8.3 million pixels).

How to resize images while maintaining aspect ratio?

Enter original resolution to confirm aspect ratio, then specify new width or height with that ratio. The corresponding dimension calculates automatically. This enables distortion-free resizing.

What are optimal aspect ratios for Instagram and YouTube?

Instagram: Feed posts 1:1 (1080x1080), Stories 9:16 (1080x1920). YouTube: 16:9 (1920x1080 recommended). YouTube accepts other ratios, but 16:9 is standard.

What is the aspect ratio of 2560x1440?

2560x1440 is 16:9 aspect ratio (simplifies to 16:9). Also called WQHD (Wide Quad HD), approximately 1.8x higher resolution than Full HD. Popular size for gaming monitors.

What happens when watching 16:9 videos on 21:9 monitor?

16:9 videos on 21:9 monitors display black bars (letterboxing) on left and right sides. Stretching the video causes distortion, so letterboxing is the correct viewing method.

What's the difference between aspect ratio and resolution?

Aspect ratio is the "proportion" (e.g., 16:9), while resolution is actual "pixel count" (e.g., 1920x1080). Same aspect ratio can have different resolutions (e.g., 16:9 includes 1280x720, 1920x1080, 3840x2160, etc.).

Why did 16:9 become the standard?

16:9 became standard to bring widescreen cinema experience to TV, and because human vision is wider horizontally. It provides wider image viewing than 4:3 and increases immersion.

How accurate is this tool's calculation?

Uses integer arithmetic for pixel-accurate calculations. GCD calculation employs Euclidean algorithm, enabling mathematically precise aspect ratio simplification.