Aspect Ratio Calculator
Calculate dimensions for any aspect ratio — for images, videos, and responsive design.
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Common Aspect Ratios
Common Screen Resolutions at 16:9
| Name | Width | Height | Use |
|---|---|---|---|
| 720p HD | 1280px | 720px | YouTube, streaming |
| 1080p Full HD | 1920px | 1080px | YouTube, Vimeo, displays |
| 1440p QHD | 2560px | 1440px | High-res displays |
| 4K UHD | 3840px | 2160px | 4K content |
| 360p | 640px | 360px | Mobile low |
| 480p SD | 854px | 480px | Mobile standard |
Frequently Asked Questions
Why is 16:9 the standard video aspect ratio?▼
16:9 (1.778:1) became the standard for HDTV and digital video because it's a compromise between the 4:3 TV standard and 2.39:1 cinema widescreen. It was chosen in the 1980s by SMPTE as the geometric mean between 4:3 and 2.39:1 — it letterboxes or pillarboxes less when displaying either format.
What is a 1.91:1 aspect ratio used for?▼
1.91:1 (approximately 1200×628px) is the recommended size for Open Graph images — the preview card when your page is shared on Facebook, LinkedIn, and other platforms. It's also used for Twitter large card images. Google Discover recommends 1200px wide minimum images at this ratio.
How do I maintain aspect ratio in CSS?▼
Modern CSS: use aspect-ratio: 16 / 9; on the element. The padding-top trick still works for older browsers: set padding-top: 56.25% (9/16 = 0.5625) on a position:relative container with position:absolute children. Or use intrinsicsize attribute on videos.
What aspect ratio should I use for Instagram?▼
Instagram supports: 1:1 (square) for feed posts, 4:5 (portrait, max vertical space in feed), 1.91:1 (landscape), and 9:16 for Reels and Stories. 4:5 portrait gets the most screen real estate in the feed. Minimum 1080px width for all formats.