Aspect Ratio Calculator

Enter the original width and height, then a new side. With the aspect lock on, the other side follows this formula: new height = new width × (original height ÷ original width).

A 1920 × 1080 frame with a new width of 1280 becomes 720 tall. Width or height of zero is an error, because the ratio divides by those numbers.

Resize one side

New size

Enter a width and height.

Aspect questions

What size is 1920 × 1080 at a width of 1280?

720 tall, when the lock is on. New height = 1280 × (1080 ÷ 1920).

Can I start from a new height instead?

Yes. Edit the new height field. The calculator then uses new width = new height × (original width ÷ original height).

Why is zero rejected?

The ratio divides by width or height. Zero would not produce a finite size, so the error sits on that field.