The formula
Print width (inches) = pixel width ÷ PPI. Multiply by 25.4 for millimetres. Pixels needed = print width in inches × PPI.
FAQ
- How many pixels do I need for an 8 × 10 inch print?
- At 300 PPI: 2400 × 3000 pixels. At 150 PPI (viewed from further away): 1200 × 1500 pixels.
- Is PPI the same as DPI?
- People often use them interchangeably. Strictly, PPI is pixels in the image; DPI is ink dots the printer lays down. For sizing a print, PPI is the number that matters.