Quick answer

Image resolution tells you how many pixels an image contains across its width and height. For printing, PPI describes how densely those pixels are placed over physical inches.

Original example

One image, two print sizes

A 3000 by 2000 pixel image measures 10 by about 6.67 inches at 300 PPI. At 150 PPI, the same pixels cover 20 by about 13.33 inches. Changing that calculation does not create extra image detail.

Interactive tool

Calculated print size

10 × 6.6667 in

25.4 × 16.9333 cm

PPI describes image pixels per inch. Printer DPI is a different measurement.

Pixels and print size

Pixel dimensions describe the digital grid. PPI connects that grid to inches for a print-size calculation. Printer DPI describes printer dots and is a different measurement.

The calculation estimates geometry only. Paper, printer, viewing distance, editing, and the source image also affect how a print looks.

Common misunderstandings

  • Changing a PPI label alone does not resample an image or add pixels.
  • Image PPI and printer DPI are related to different parts of the printing process.

Related answers

Sources

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