Aspect Ratio Calculator
Simplify ratios or lock one to solve dimensions.
×
16:9
Simplified ratio
1.778
Decimal
| 1280 × 720 |
| 1920 × 1080 |
| 2560 × 1440 |
| 3840 × 2160 |
How to use the Aspect Ratio Calculator
- 1 Enter a width and height to see the simplified ratio and decimal value.
- 2 Or lock a ratio (a preset like 16:9, or a custom one) and enter one dimension to solve the other.
- 3 Check the common-resolutions table for that ratio to pick a standard size.
Examples
- ▸ 1920×1080 simplifies to 16:9 (1.778).
- ▸ Locking 16:9 and entering 1280 width solves height = 720.
Frequently asked questions
How is the aspect ratio simplified?
Width and height are divided by their greatest common divisor (GCD), the same method used to reduce a fraction — so 1920×1080 reduces to 16:9.
How do I find a missing dimension from a ratio?
Lock the ratio you want (like 4:3), enter the dimension you know, and the calculator multiplies by the ratio to solve the other — e.g. a 4:3 image that is 800px wide is 600px tall.
Why do my resized dimensions look slightly off?
Pixel dimensions must be whole numbers, so the solved value is rounded to the nearest pixel, which can shift the exact ratio by a fraction of a percent — this matches how real image and video tools round as well.