Aspect Ratio Calculator
Calculate aspect ratios for images, videos, and screens. Enter width and height to find the ratio, or lock a ratio and calculate missing dimensions. Common presets for 16:9, 4:3, 1:1, and more. Free and private.
Common Aspect Ratios
What Is Aspect Ratio?
Aspect ratio is the proportional relationship between the width and height of an image, video, or screen. It is expressed as two numbers separated by a colon, like 16:9 or 4:3. The aspect ratio calculator helps you maintain correct proportions when resizing images, designing layouts, or choosing display resolutions.
Common Aspect Ratios
16:9 — HD video, YouTube, most monitors
4:3 — Classic TV, iPad, presentations
1:1 — Instagram square, profile pictures
9:16 — TikTok, Instagram Reels, Stories
21:9 — Ultrawide monitors, cinematic
Aspect Ratio for Video
Most modern video content uses 16:9 (widescreen). YouTube, Netflix, and most streaming platforms default to this ratio. Vertical video for TikTok and Instagram Reels uses 9:16. Cinematic films often use wider ratios like 21:9 or 2.39:1. When editing video, maintaining the correct aspect ratio prevents black bars or stretching.
Aspect Ratio for Web Design
Web designers use aspect ratios to create responsive image containers, hero sections, and video embeds. CSS provides the aspect-ratio property to maintain proportions without JavaScript. Common web image ratios include 16:9 for hero banners, 1:1 for thumbnails, and 4:3 for product photos.