Aspect Ratio Calculator — Calculate Image & Video Dimensions While Maintaining Proportions
Enter any width or height and instantly get the matching dimension while maintaining your aspect ratio. Perfect for designers, video editors and developers.
What is the Aspect Ratio Calculator?
The Aspect Ratio Calculator lets you instantly find the correct width or height when resizing an image or video while maintaining its original proportions. Enter your original dimensions and a new width or height, and the calculator finds the missing value — preventing stretched or distorted images.
How to Use — Step-by-Step
Enter your original width and height — the ratio is detected and shown instantly.
Type a new width or height in the right panel — the matching dimension is calculated.
Or click a preset (16:9, 9:16, 1:1, etc.) to load common aspect ratios instantly.
📐 Common Aspect Ratios Reference
Key Features
- ✓ Instant calculation: Type any dimension and the other updates in real time.
- ✓ Visual box preview: See a proportionally correct rectangle that updates as you type.
- ✓ 12 common presets: Load 16:9, 9:16, 1:1, 4:5, 4K, Full HD and more in one click.
- ✓ Ratio detection: Automatically simplifies dimensions to show the clean ratio (e.g. 1920:1080 → 16:9).
Frequently Asked Questions
What is aspect ratio?
Aspect ratio is the proportional relationship between an image's width and height, expressed as W:H (e.g., 16:9).
What is 16:9 in pixels?
Common 16:9 resolutions: 1280×720 (HD), 1920×1080 (Full HD), 2560×1440 (QHD), 3840×2160 (4K). Use the calculator to find any custom size.
What aspect ratio is best for YouTube?
YouTube recommends 16:9 (1920×1080 Full HD). Shorts use 9:16 (1080×1920). Thumbnails are 1280×720.
What aspect ratio is best for Instagram?
1:1 square (1080×1080), 4:5 portrait (1080×1350), or 16:9 landscape (1080×608). Reels use 9:16 (1080×1920).
Is this calculator free?
Yes, 100% free with no signup required.
📽️ Why Aspect Ratio Matters for Social Media
In 2026, social media algorithms prioritize high-quality, vertically-aligned content. Using the correct ratio isn't just about aesthetics; it's about engagement and SEO .
- Instagram Reels & YouTube Shorts: Require a 9:16 vertical ratio (1080x1920). Content that doesn't fill the screen sees lower reach.
- LinkedIn Carousels: Work best with 1:1 or 4:5 ratios to ensure text remains legible on both mobile and desktop feeds.
- Video Production: Cinematic 21:9 or standard 16:9 widescreen determines the "feel" of your project.
This tool ensures you never have to guess. Just plug in your desired height or width and let our aspect ratio calculator do the rest.