Enter dimensions
Type width and height manually or read them from a local image.
RATIO · PROPORTIONAL SIZE
Calculate image proportions
Simplify image aspect ratios and calculate proportional dimensions from manual values or a locally inspected image.
Calculate an aspect ratio
Optional local imageSimplified ratio16:9
Proportional dimensions1280 × 720
The new height is rounded to the nearest whole pixel.
HOW IT WORKS
A private browser workflow
Your files stay in this tab and are not sent to an image-processing server.
Simplify the ratio
The greatest common divisor reduces dimensions to their smallest whole-number ratio.
Choose a new width
Set one target dimension without guessing the other.
Use the result
Copy the proportional whole-pixel width and height into your editor or layout.
Common questions
Does this resize my image?
No. It only calculates ratios and dimensions.
How are fractional pixels handled?
Calculated dimensions are rounded to the nearest whole pixel.
Is an uploaded image sent anywhere?
No. Only its dimensions are read locally.