How to use the Aspect Ratio Calculator
Enter a ratio and a width to get the matching height (or the other way round), or enter a size to find its simplified ratio. Handy for exporting videos, thumbnails and banners at the right dimensions.
Popular sizes
- YouTube video 16:9 — 1920 × 1080 or 3840 × 2160
- Reels, Shorts, stories 9:16 — 1080 × 1920
- YouTube thumbnail — 1280 × 720
- Instagram portrait 4:5 — 1080 × 1350
Frequently asked questions
What aspect ratio are reels and YouTube Shorts?
Vertical 9:16, typically exported at 1080 × 1920.
How do I find the ratio of 1366 × 768?
Divide both by their greatest common divisor. Some sizes only approximate a standard ratio — 1366 × 768 is roughly 16:9.