How do I calculate the aspect ratio from width and height?

Divide both the width and height by their Greatest Common Divisor (GCD). For example, for 1920x1080: GCD is 120, so 1920/120 : 1080/120 = 16:9. Our calculator does this automatically — just enter your pixel dimensions.

What aspect ratio is 1920x1080?

1920x1080 has an aspect ratio of 16:9. This is the standard Full HD widescreen ratio used by most monitors, TVs, and video platforms. Other common 16:9 resolutions include 1280x720 (HD), 2560x1440 (QHD), and 3840x2160 (4K UHD).

What is the best aspect ratio for YouTube videos?

YouTube recommends 16:9 for standard videos (1920x1080 or 3840x2160). For YouTube Shorts, use 9:16 (1080x1920). YouTube will add black bars (letterboxing) if your video doesn't match 16:9, so it's best to shoot and export in the correct ratio.

How do I convert from 4:3 to 16:9?

You cannot convert without either cropping (losing content at top/bottom) or adding letterbox bars (black bars on sides). For a 4:3 image at 1024x768, converting to 16:9 would give 1024x576 (cropped) or 1365x768 (with bars). Our resize tool helps you calculate the exact dimensions.

What aspect ratio should I use for Instagram?

Instagram supports multiple ratios: 1:1 (1080x1080) for square feed posts, 4:5 (1080x1350) for portrait feed posts (recommended — takes up more screen space), 9:16 (1080x1920) for Stories and Reels, and 16:9 (1080x608) for landscape posts.

What is the difference between 16:9 and 16:10?

16:9 (1.778) is the standard for TVs and video content. 16:10 (1.6) is slightly taller and was common in older laptops and the MacBook Pro line. 16:10 gives a bit more vertical space, which is useful for productivity. Common 16:10 resolutions: 1920x1200, 2560x1600.

Aspect Ratio Calculator

Our aspect ratio calculator helps designers, videographers, and developers work with image and video dimensions. Enter width and height to find the simplified ratio, provide a ratio and one dimension to calculate the other, or resize any resolution while maintaining its proportions. Includes quick presets for all major social media platforms and standard screen resolutions from HD to 8K.

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calendar_today Updated: April 2026

auto_awesome AI Insights AI

New

Width (px)

Height (px)

calculate Result

16:9

Aspect Ratio

1.778

Decimal

120

GCD

Landscape

Orientation

Total: 2,073,600 pixels

devices Platform Presets

preview Preview

16:9

1920 × 1080 px

grid_view Quick Ratios

table_chart Common Resolutions

Name	Resolution	Ratio
8K UHD	7680×4320	16:9
4K UHD	3840×2160	16:9
QHD	2560×1440	16:9
Full HD	1920×1080	16:9
HD	1280×720	16:9
UW FHD	2560×1080	21:9
XGA	1024×768	4:3
Square	1080×1080	1:1

tips_and_updates Tips

• 16:9 is the most common widescreen ratio, used for HD (1280x720), Full HD (1920x1080), and 4K (3840x2160)
• 4:3 was the standard ratio for older TVs and monitors — still used for presentations and some tablets
• Instagram posts use 1:1 (square), while Stories and Reels use 9:16 (vertical)
• YouTube recommends 16:9 for standard videos and 9:16 for Shorts
• 21:9 (ultrawide) is popular for cinematic content and ultrawide monitors
• When resizing, always lock the aspect ratio to avoid stretching or squishing your images
• 3:2 is the classic photography ratio used by most DSLR cameras
• Use the decimal ratio (e.g., 1.778 for 16:9) for quick mental math when scaling

How to Use This Calculator

calculate

Find a Ratio

Enter width and height in pixels to instantly calculate the simplified aspect ratio using GCD.

straighten

Calculate Dimension

Select a preset ratio and enter one dimension to find the matching width or height.

aspect_ratio

Resize Proportionally

Enter your current dimensions and a new width or height to resize while keeping the same aspect ratio.

The Formula

The aspect ratio is found by dividing both width and height by their Greatest Common Divisor (GCD). For example, 1920x1080: GCD(1920,1080) = 120, so the ratio is 1920/120 : 1080/120 = 16:9. To find a missing dimension: Height = Width / (RatioW / RatioH), or Width = Height * (RatioW / RatioH).

Ratio = W/GCD(W,H) : H/GCD(W,H)

lightbulb Variables Explained

W Width in pixels
H Height in pixels
GCD Greatest Common Divisor of width and height
Ratio Simplified aspect ratio (e.g., 16:9)

tips_and_updates Pro Tips

16:9 is the most common widescreen ratio, used for HD (1280x720), Full HD (1920x1080), and 4K (3840x2160)

4:3 was the standard ratio for older TVs and monitors — still used for presentations and some tablets

Instagram posts use 1:1 (square), while Stories and Reels use 9:16 (vertical)

YouTube recommends 16:9 for standard videos and 9:16 for Shorts

21:9 (ultrawide) is popular for cinematic content and ultrawide monitors

When resizing, always lock the aspect ratio to avoid stretching or squishing your images

3:2 is the classic photography ratio used by most DSLR cameras

Use the decimal ratio (e.g., 1.778 for 16:9) for quick mental math when scaling

Calculate Aspect Ratios for Images, Videos & Screens

Our free aspect ratio calculator helps you find the ratio from any pixel dimensions, calculate missing width or height for a given ratio, and resize images while maintaining proportions. Perfect for video editors, photographers, web designers, and social media creators.

Aspect Ratio From Pixels

Enter any width and height to find the simplified aspect ratio using the GCD (Greatest Common Divisor) method. For example, 1920x1080 simplifies to 16:9, and 2560x1440 simplifies to 16:9 as well. Our calculator also shows the decimal ratio for quick reference.

16:9 Resolution Calculator

16:9 is the standard widescreen ratio used for HD, Full HD, 4K, and 8K resolutions. Common 16:9 resolutions include 1280x720 (HD), 1920x1080 (Full HD), 2560x1440 (QHD), 3840x2160 (4K UHD), and 7680x4320 (8K). Enter any width to instantly calculate the matching 16:9 height.

Social Media Aspect Ratios

Each social media platform has recommended aspect ratios: YouTube (16:9, 9:16 for Shorts), Instagram (1:1 square, 4:5 portrait, 9:16 Stories/Reels), TikTok (9:16), Twitter/X (16:9, 2:1 header), Facebook (1.91:1 link, 9:16 Stories). Use our platform presets to get the exact pixel dimensions.

Frequently Asked Questions

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