Question 1

What is an aspect ratio?

Accepted Answer

Aspect ratio is the proportional relationship between an image or screen's width and height, written as W:H. Common ones are 16:9 (widescreen video, TVs), 4:3 (older TVs, iPads), 1:1 (Instagram square), 9:16 (vertical video, TikTok) and 21:9 (ultrawide cinema). The ratio determines the shape regardless of actual pixel size.

Question 2

How do I calculate aspect ratio from pixels?

Accepted Answer

Divide width and height by their greatest common divisor (GCD). For 1920×1080: GCD is 120, so the ratio is 16:9. For 1080×1920 (portrait): GCD is 120, so 9:16. Many calculators and tools (like this one) automate the math instantly.

Question 3

Which aspect ratio is best for social media?

Accepted Answer

It depends on the platform: Instagram feed posts use 1:1 or 4:5, Stories/Reels use 9:16, Twitter/X uses 16:9 for images, LinkedIn prefers 1.91:1, YouTube uses 16:9 for landscape and 9:16 for Shorts. Pick the platform's native ratio to avoid cropping.

Question 4

What is the difference between 16:9 and 4:3?

Accepted Answer

16:9 is widescreen — used by modern TVs, monitors, YouTube and HD video. 4:3 is the older standard — used by traditional TVs, iPad (some modes), some camera formats and older computer monitors. 16:9 is about 78% wider than tall; 4:3 is 33% wider than tall.

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