How many pixels does an 8 × 10 print need?
At 300 PPI, an 8 × 10 inch print needs 2,400 × 3,000 pixels, or 7.2 megapixels. This calculation describes resolution; it does not guarantee that the source is sharp or free from compression artifacts.
Why the calculator rounds up
A fractional pixel cannot exist. Rounding each dimension upward ensures the finished file does not fall just below the requested density.