Aspect Ratio Calculator
Work out the ratio for any dimensions, or lock a ratio and scale freely.
Aspect Ratio
16:9
Decimal
1.7778 : 1
Common ratios, apply to keep the current width
Calculate aspect ratios and proportional dimensions, enter a ratio and one side to get the other, or simplify a width and height to its ratio. Instant and on-device.
How to use Aspect Ratio
- Enter a known width or height.
- Enter the target ratio (e.g. 16:9), or the other dimension.
- Read the missing value instantly.
- Use it to size images, video, or layouts.
Frequently asked questions
What is an aspect ratio?
It's the proportional relationship between width and height, written like 16:9 or 4:3. It stays constant as you scale a shape up or down.
How do I keep proportions when resizing?
Lock the ratio and change one dimension; the tool computes the other so the image is not stretched or squashed.
Is anything I enter saved?
No. Calculations run locally in your browser; nothing is stored.