Aspect Ratio Calculator — Maintain Exact Image & Video Proportions
Resize any image or video without distortion. Enter your original dimensions, type a new width or height, and the calculator instantly finds the missing value. Works for 16:9, 4:3, 1:1, 9:16, and any custom ratio. Free. No login. 100% in your browser.
What is the Aspect Ratio Calculator?
The Aspect Ratio Calculator by WorldOfTools lets you instantly find the correct width or height when resizing an image or video while maintaining its exact original proportions. Enter your original dimensions and a new width or height — the calculator computes the missing value automatically, preventing stretched or distorted output.
It also detects and displays the simplified ratio (like 16:9, 4:3, or 1:1) for any pair of dimensions you enter, with a real-time visual preview of the proportions.
How to Use — Step by Step
Enter your original width and height — the ratio is detected and shown instantly in the black display above.
Type either a new width or new height — the other dimension is automatically calculated and highlighted in yellow.
Or click a preset button (16:9, 9:16, 1:1, etc.) to instantly load popular aspect ratios used across social media and video platforms.
Use Swap W/H to flip orientation, Reset to clear fields, or Copy Result to copy dimensions to your clipboard.
📐 Common Aspect Ratios Reference
| Ratio | Common Use | Example Resolutions |
|---|---|---|
| 16:9 | YouTube, TV, monitors, Zoom calls | 1280×720, 1920×1080, 3840×2160 |
| 9:16 | YouTube Shorts, Reels, Stories, TikTok | 1080×1920 |
| 1:1 | Instagram square posts, profile pictures | 1080×1080 |
| 4:5 | Instagram portrait posts | 1080×1350 |
| 4:3 | Classic TV, old monitors, presentations | 1024×768, 1280×960 |
| 21:9 | Ultrawide monitors, cinematic film | 2560×1080, 3440×1440 |
| 3:2 | DSLR cameras, 35mm film | 4500×3000, 6000×4000 |
| 1.91:1 | LinkedIn, Facebook links, Open Graph images | 1200×628 |
Why Aspect Ratio Matters for Social Media
Uploading an image or video with the wrong aspect ratio causes platforms to crop, stretch, or letterbox your content — often cutting out important details or making it look unprofessional. Each platform has specific requirements:
Instagram Feed accepts 1:1 (square), 4:5 (portrait), or 1.91:1 (landscape). YouTube requires 16:9 for regular videos and 9:16 for Shorts. LinkedIn recommends 1.91:1 (1200×628) for link previews and shared images. Using this calculator ensures you always export at the exact pixel dimensions required — no distortion, no cropping surprises.
Frequently Asked Questions
What is an aspect ratio?
An aspect ratio is the proportional relationship between the width and height of an image or video, expressed as W:H (e.g., 16:9). It determines how wide or tall the content appears. When you resize content while keeping the ratio the same, nothing gets stretched or distorted.
How do I calculate the missing dimension when resizing?
Enter your original width and height, then type either the new width or new height you want. This calculator uses the formula new height = (new width ÷ original width) × original height to compute the missing value instantly.
What aspect ratio should I use for YouTube videos?
16:9 is the standard for YouTube. For Shorts and vertical content, use 9:16. Our preset buttons let you load these ratios instantly so you can scale to exact pixel dimensions like 1920×1080 (Full HD) or 3840×2160 (4K Ultra HD).
What is the best aspect ratio for Instagram posts?
For Instagram feed posts: 1:1 (square, 1080×1080) is most universal. For portrait posts use 4:5 (1080×1350) which takes up more vertical feed space. For Stories and Reels use 9:16 (1080×1920).
Is this tool free and does it store my data?
Yes — completely free with no login required. All calculations run locally in your browser using JavaScript. No dimension data is ever sent to any server, making it 100% private.