Media & Design4 min read•July 3, 2026
Aspect Ratio Cheatsheet: Calculating Image & Video Dimensions for Social Media
Master proportional scaling for 16:9 YouTube thumbnails, 9:16 TikTok Reels, 1:1 Instagram posts, and 21:9 ultrawide banners.
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Reviewed by the GreenCode Media & Design Editorial Desk
Last Updated: July 3, 2026
Disclaimer: Calculations and results provided by this tool are mathematical estimates for informational and educational purposes only. They do not constitute professional financial, tax, or legal advice.
Featured Utility Tool
Open Tool Now →Aspect Ratio & Resolution Scaler
Introduction
Publishing images or videos with wrong aspect ratios causes awkward cropping, pillarboxing, or distortion on modern screens.
Step-by-Step Instructions
- Select ratio presets (16:9, 9:16, 4:3, 1:1, 21:9) or enter custom ratio values.
- Input target width in pixels.
- Get instant proportional height calculation.
Key Use Cases
- Video Editing: Calculate project render resolutions before exporting.
- Social Media Design: Resize banners and post graphics accurately.
Frequently Asked Questions
What is the recommended aspect ratio for YouTube thumbnails?
The standard aspect ratio for YouTube thumbnails and HD video playback is 16:9 (1920x1080 px).