Aspect Ratio Calculator
Resize width and height while keeping the same aspect ratio.
Results update as you type.
About this calculator
An aspect ratio calculator keeps an image or screen in proportion when you resize it. Enter the original width and height to see the simplified ratio (like 16:9), then type a new width to get the matching height that preserves the shape. Handy for photos, video frames, monitors and web layouts.
Frequently asked questions
How do I keep an image in proportion when resizing?
Divide the original width by the original height to get the ratio, then multiply your new width by (original height ÷ original width). Scaling 1920×1080 down to a 1280 width gives a height of 1280 × 1080 ÷ 1920 = 720.
What does an aspect ratio like 16:9 mean?
It is the simplified proportion of width to height. 1920:1080 both divide by 120 to give 16:9, meaning 16 units of width for every 9 of height — the standard for HD video and most monitors.
Results are estimates for general guidance only, not financial, medical or tax advice.