Free tool
Aspect Ratio Calculator
Lock an aspect ratio, enter one dimension, and get the other instantly. Handy presets for video, photo, square, and mobile.
Ratio:
Width
px
×
Height
px
16:9
FAQ
How do I keep an aspect ratio when resizing?
Pick a ratio (or enter a custom one), then type either the width or the height — the other dimension is calculated automatically to preserve the ratio.
What ratio is best for mobile screens?
Most modern phones are close to 9:19.5 in portrait. For full-screen mobile design, 9:16 is a common, simple approximation.
Now design the whole app.
Bender turns a prompt into a full set of themed mobile screens you can edit, test, and export. Free to start — no credit card.
Try Bender free