What is aspect ratio?

The ratio of width to height, e.g. 16:9 (widescreen) or 4:3 (old).

How do I scale without distortion?

Keep the same ratio: multiply new width by original height/width.

Aspect Ratio Calculator

Calculate the missing dimension of an image or video while keeping the aspect ratio. Scale resolution without distortion.

Original width: 1,920 px

Original height: 1,080 px

New width: 1,280 px

720 px

New height

Aspect ratio	1.778 :1
New height	720 px

ℹ️ New height = new width × (original height / original width). 16:9 = 1.778.

The aspect ratio calculator works out the missing dimension of an image or video so that the original proportions stay intact. It scales a resolution correctly without stretching or squashing the picture.

How the calculator works and what it’s for▾

How the ratio is preserved

The new height is found with new height = new width × (original height / original width). The relationship between the original width and height is therefore carried over to the new size.

For example, a 16:9 ratio corresponds to a factor of 1.778, so at 1,280 pixels wide the height becomes 720 pixels.

What you enter and what you get

Enter the original width and height plus the new width you want, all in pixels. The calculator shows the aspect ratio and works out the missing new height.

This lets you quickly check what dimensions the image will scale to before editing or publishing.

What it is used for

It suits cropping photos, choosing video export settings and sizing image elements on web pages.

It is needed whenever an image must be resized but its proportions should stay the same.

Common mistakes

The most common error is changing only one dimension on its own, which distorts the image. Calculating the missing dimension with this formula avoids stretching.

Remember to round the final pixel count to a whole number, since screens do not use partial pixels.

🔄 Reviewed June 2026