Aspect ratio calculator
Type a width and a height to get the exact ratio, or pick a ratio and one side to get the other. Solved sides are rounded to even pixels, and a live preview shows the shape.
Enter a width and a height to see the ratio.
Choose a ratio and enter one side to see the other.
How it works
- 01
Enter a size
Type a width and a height, or choose a ratio such as 9:16 and give one side.
- 02
Read the ratio or the missing side
The exact ratio is reduced to its simplest form. When it is not a common one, the closest common ratio is named too.
- 03
Check the preview
A box drawn at the ratio shows the shape before you resize anything.
What you get
- Exact ratio by greatest common divisor, so 1920 by 1080 gives 16:9.
- Names the closest common ratio and how far off you are, for sizes like 1366 by 768.
- Reads 16:9, 16/9, 16x9 or a decimal like 1.78.
- Free, no signup, and nothing you type is sent to a server.
Frequently asked questions
How is the aspect ratio worked out?
Width and height are both divided by their greatest common divisor. 1920 by 1080 share a divisor of 120, which leaves 16:9.
Why does 1366 by 768 not give a short ratio?
It reduces to 683:384, which is exact but awkward. The tool also names the closest common ratio, 16:9, and says by how much your size differs from it.
Why are solved sides rounded to an even number?
Many video encoders need even dimensions, so a solved side is rounded to the nearest even pixel. When the exact value sits halfway between two even numbers, the larger one is used.
Is anything I type stored?
No. Everything is worked out in your browser as you type. Nothing you type is sent to a server.
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