Simplify ratio
Divide width:height by the greatest common divisor.
Aspect Ratio Calculator
Calculate & Convert Aspect Ratios and Screen Sizes
Calculation Mode
Common Ratios
Find Ratio
px
px
Aspect ratio describes how wide a frame is compared with its height
Images, videos, thumbnails, and screens look right when the ratio is preserved. This calculator finds the simplified ratio from width and height, or calculates a missing dimension from a target ratio.
Core formulas
Find height
height = width × ratioHeight / ratioWidth
Find width
width = height × ratioWidth / ratioHeight
How to use
- Enter the original width and height in pixels to identify the current ratio.
- Choose a preset such as 16:9, 4:3, or 1:1, or enter a custom ratio.
- Lock one dimension and use the calculated other dimension for your design or export.
Frequently asked questions
Where is 16:9 commonly used?
It is the standard wide format for YouTube videos, many monitors, slides, and streaming layouts.
What should I do with decimal pixel results?
Pixels must be whole numbers, so round to the nearest integer unless a platform gives an exact recommended size.
Why does changing the ratio stretch my image?
Changing width and height independently breaks the original ratio. Calculate the dependent dimension to avoid distortion.
This tool is for general screen and media sizing. For ads, print, broadcast, or platform delivery, confirm the latest required specifications.