Aspect Ratio Calculator
Calculate the aspect ratio of any resolution, resize images proportionally, and look up screen resolutions for popular devices. Includes social media and video format guides.
How to Use
- Enter width and height to calculate the aspect ratio
- Or switch to Resize mode to scale proportionally
- Use quick-select buttons for common ratios (16:9, 4:3, 1:1)
- View the visual preview of the aspect ratio
What Is an Aspect Ratio?
An aspect ratio expresses the proportional relationship between the width and height of an image, video, or screen. Written as two numbers separated by a colon (like 16:9), it ensures content displays correctly without stretching or cropping across different devices and platforms.
Aspect ratios are fundamental in digital media, photography, film, and responsive web design. The ubiquitous 16:9 ratio dominates HD and 4K video, while 4:3 remains common in presentations and older displays. Social media platforms each mandate specific ratios — Instagram favors 1:1 and 4:5, TikTok uses 9:16 — making an aspect ratio calculator essential for content creators.
Popular Use Cases
Image Resizing
Calculate the correct height for a given width (or vice versa) to resize images without distortion or unwanted cropping.
Video Production
Determine export dimensions for different platforms: widescreen for YouTube, vertical for TikTok, square for Instagram feed.
Responsive Web Design
Set CSS aspect ratios for embedded media, hero images, and card layouts that scale proportionally across screen sizes.
Print Layout
Match digital designs to standard print sizes like A4, letter, or poster dimensions while preserving proportions.
Aspect Ratio Tips
Maintain Proportions Always
Lock the aspect ratio when resizing to prevent stretched or squished images. Most editors have a lock icon or constrain toggle.
Use Standard Ratios
Stick to common ratios (16:9, 4:3, 1:1) for maximum compatibility. Custom ratios may cause letterboxing or pillarboxing on standard displays.
Follow Social Media Guidelines
Each platform has optimal sizes: Instagram posts (1080x1080), YouTube thumbnails (1280x720), Twitter headers (1500x500).
Account for Retina Displays
Export images at 2x resolution for retina screens. A 1200x630 OG image should be created at 2400x1260 for sharp display on HiDPI devices.
Common Aspect Ratios Compared
| Ratio | Decimal | Primary Use | Example Resolution |
|---|---|---|---|
| 16:9 | 1.778 | HD/4K video, YouTube, monitors | 1920 x 1080 |
| 4:3 | 1.333 | Presentations, classic TV, iPad | 1024 x 768 |
| 1:1 | 1.000 | Instagram feed, profile pictures | 1080 x 1080 |
| 21:9 | 2.333 | Ultrawide monitors, cinematic film | 2560 x 1080 |
| 9:16 | 0.563 | TikTok, Instagram Reels, Stories | 1080 x 1920 |