Aspect Ratio Calculator
Calculate and simplify aspect ratios (16:9, 4:3), solve missing width or height while keeping proportions, and check common video and social sizes.
About the Aspect Ratio Calculator
The Aspect Ratio Calculator takes any width and height and reduces them to the simplest ratio — 1920×1080 becomes 16:9, 1080×1350 becomes 4:5 — and tells you when the ratio matches a common standard used by YouTube, Instagram, TikTok or cinema.
The missing-dimension solver is the part you'll use most: keep the original ratio, type a new width (or height), and get the other side instantly. Perfect for resizing images and videos without stretching, setting CSS container sizes, or scaling artboards.
A reference table of common resolutions — 720p, 1080p, 1440p, 4K, Instagram post/portrait/story and OG image sizes — is included so you don't have to memorize pixel dimensions.
How to Use the Aspect Ratio Calculator
- 1Enter your original width and height to see the simplified ratio.
- 2Check whether it matches a common standard like 16:9 or 4:5.
- 3Enter a new width or height in the solver to get the matching other dimension.
- 4Use the resolutions table for standard video and social media sizes.
Frequently Asked Questions
What aspect ratio is 1920×1080?
16:9 — both numbers divide by 120. It's the standard widescreen ratio for YouTube, TV and most monitors; 1280×720 and 3840×2160 (4K) are the same ratio.
How do I resize an image without stretching it?
Enter the original width and height, then type your target width in the solver — the calculator returns the height that preserves the ratio. For a 1920×1080 image at 1280 wide, the height is 720.
What is the best aspect ratio for Instagram?
1:1 (1080×1080) for classic posts, 4:5 (1080×1350) for portrait posts that take more feed space, and 9:16 (1080×1920) for Stories and Reels.
What does a ratio like 1.91:1 mean?
It's the width divided by the height with the height normalized to 1. Facebook link previews and OG images use 1.91:1, which is 1200×630 pixels.