How this calculator works
If the image and target size have different aspect ratios, horizontal and vertical PPI can differ. This calculator uses the lower value for a conservative quality assessment.
PPI = pixels ÷ (centimeters ÷ 2.54)
Frequently asked questions
Why are there two PPI values?
Width and height can produce different values when the target aspect ratio does not match the image.
Which PPI determines quality?
The lower horizontal or vertical value is the limiting resolution and is used for the rating.
Does increasing a metadata PPI value add detail?
No. Changing metadata without adding real pixels only changes the interpreted physical size.