Question 1

What is aspect ratio?

Accepted Answer

Aspect ratio is the proportional relationship between an image's width and height, written as two numbers separated by a colon (for example 16:9). It tells you how wide something is relative to how tall it is — independent of actual size.

Question 2

How do I calculate the missing dimension?

Accepted Answer

Enter the known width and the ratio, then click Calculate. The tool fills in the height (or vice-versa). It also shows what the image looks like at common resolutions while keeping that exact ratio.

Question 3

Can I lock one side and resize the other?

Accepted Answer

Yes. Type any width OR height, pick a ratio from the presets, and the other dimension updates instantly. Use this to keep an image perfectly proportioned when resizing for Instagram, YouTube, banners or print.

Question 4

Is my data sent anywhere?

Accepted Answer

No. All math runs in your browser. Nothing is uploaded, nothing is stored.