About the Pixels to Print Size Calculator
This calculator converts a digital image's pixel dimensions into the physical size it will occupy when printed, using the standard resolution formula that photo labs, printers, and design software all rely on: print size equals pixel count divided by the chosen resolution, measured in pixels per inch (PPI).
The formula
Given an image that is W pixels wide and H pixels tall, printed at a resolution of PPI pixels per inch:
- Print width (inches) = W ÷ PPI
- Print height (inches) = H ÷ PPI
- To get centimeters, multiply each inch value by 2.54 (1 inch = 2.54 cm exactly).
For example, a 4000 × 3000 pixel image (12 megapixels) printed at 300 PPI yields a 13.33 × 10 inch print (33.87 × 25.4 cm). Printed at 150 PPI instead, the same pixels stretch to 26.67 × 20 inches — twice as large, but at half the pixel density, so it looks noticeably softer up close.
Choosing a print resolution (PPI)
PPI (pixels per inch) describes how densely an image's pixels are packed on paper. There is no single "correct" value — the right PPI depends on viewing distance and the print's purpose:
- 300 PPI — the standard for photo prints, magazines, and anything viewed up close; widely used by print labs as the default target.
- 150–200 PPI — commonly acceptable for large posters, canvas prints, and signage viewed from a few feet away.
- 100–150 PPI — usable for very large banners viewed at a distance, where individual pixels are less noticeable.
- Below 100 PPI — reserved for billboard-scale signage meant to be seen from many feet or yards away.
Practical context
This formula gives the maximum print size a file supports without upsampling (artificially adding pixels). Printing larger than the pixel count and PPI allow does not add real detail — it stretches existing pixels, which can soften the image. If you need a specific print size, work backward: multiply the desired inches by your target PPI to find the minimum pixel dimensions your image (or camera/scan setting) should have.