How to Use the Screen Aspect Ratio Finder
An aspect ratio is the simplified width-to-height proportion of a display. It's calculated using the greatest common divisor (GCD) of both pixel dimensions. For example, 1920÷120 = 16 and 1080÷120 = 9, giving a 16:9 ratio. Knowing the aspect ratio matters for video editing, monitor selection, and creating thumbnails or graphics at the right proportions.
Enter the width and height in pixels to get the simplified ratio, its common name, and a list of standard resolutions that share the same ratio.
Common Aspect Ratios Guide
- 16:9 — Standard widescreen for monitors, TVs, and YouTube
- 4:3 — Legacy standard for older monitors and presentations
- 21:9 — Ultrawide monitors (2560×1080, 3440×1440)
- 16:10 — MacBooks and some laptops (WUXGA family)
- 3:2 — Microsoft Surface devices and DSLR photos
YouTube requires 16:9 uploads. Instagram square posts are 1:1. Reels/Stories use 9:16 (vertical 16:9). Checking your source resolution's ratio before editing prevents unexpected cropping.
Frequently Asked Questions
2560×1440 (QHD / 2K) is 16:9 — the same as 1080p FHD but with 4× the pixels. It's the most common resolution for gaming monitors and high-end laptops.
Mathematically, 3440÷40 = 86 and 1440÷40 = 36, giving 43:18. But the monitor industry markets it as 21:9. This tool shows the exact GCD ratio. 21:9 monitors are sometimes called "UltraWide."
Most DSLRs shoot in 3:2 (e.g., 6000×4000). Standard 4"×6" prints are also 3:2. Micro Four Thirds cameras use 4:3. Crop to 16:9 for YouTube thumbnails.