Aspect Ratio Calculator
Solve dimensions for any ratio, or reduce a ratio
Common Resolutions by Aspect Ratio
| Ratio | Resolutions | Typical use |
|---|---|---|
| 16:9 | 1280×720 · 1920×1080 · 2560×1440 · 3840×2160 | HD / Full HD / QHD / 4K video, monitors |
| 16:10 | 1280×800 · 1920×1200 · 2560×1600 | Laptops, tablets |
| 4:3 | 800×600 · 1024×768 · 1600×1200 | Slides, legacy displays, iPad |
| 21:9 | 2560×1080 · 3440×1440 | Ultrawide monitors, cinema |
| 1:1 | 1080×1080 · 2048×2048 | Social posts, avatars |
| 9:16 | 1080×1920 · 720×1280 | Phone video, Stories, Shorts |
| 3:2 | 1080×720 · 3000×2000 | Photography, some laptops |
About This Tool
Solve the missing width or height for any aspect ratio — 16:9 video, 4:3 slides, 21:9 ultrawide, 1:1 social posts — or enter pixel dimensions to reduce them to the simplest ratio. Ideal for resizing images, video exports, and responsive layouts.
Frequently Asked Questions
What height matches 1920 pixels wide at 16:9?
1920 × 9 ÷ 16 = 1080 pixels — the standard Full HD frame.
How do I find the aspect ratio of an image?
Use the Reduce Ratio mode: enter its width and height in pixels and the tool divides both by their greatest common divisor, e.g. 1920×1080 → 16:9.
Why does my result have decimals?
Not every ratio divides pixels evenly. Round to the nearest whole pixel, or adjust the known dimension slightly for exact integers.
What is 21:9 used for?
Ultrawide monitors and cinematic video. Common 21:9-class resolutions include 2560×1080 and 3440×1440 (exactly 64:27 and 43:18).