Aspect Ratio Calculator
Simplify any width × height to its ratio (1920 × 1080 → 16:9), or find the missing side of a ratio. For screens, video, film and photos.
Example — Aspect ratio of 1920 × 108016:9
| Common shapes | Ratio |
|---|---|
| HD / 4K / 8K video, most TVs | 16:9 |
| Older TV and monitors | 4:3 |
| Cinema (DCI) | 17:9 (≈1.90:1) |
| Ultrawide monitors | 21:9 |
| Phone video, vertical (Reels/Shorts) | 9:16 |
| Classic 35 mm photo | 3:2 |
| Square social posts | 1:1 |
How we got it — the example, step by step
- Divide both sides by their greatest common divisor, 120: 1920 ÷ 120 = 16, and 1080 ÷ 120 = 9.
- As a decimal the ratio is 1.7778 — the frame is about 1.78× as wide as it is tall.
Check it backwards
Cross-multiply: 16 × 1080 = 17,280 and 9 × 1920 = 17,280 — equal, so the simplified ratio is the same shape.
Questions people also ask
What ratio is a phone video?
Vertical phone video is 9:16 — the 16:9 frame turned on its side. The calculator handles it the same way: 1080 × 1920 simplifies to 9:16.