Pixel Calculator - Convert CM, MM, Inches to Pixels (DPI)

How to Convert Physical Size to Pixels

Whether you are designing a banner for print or adjusting an image for a website, knowing the correct pixel dimensions is crucial. This calculator helps you convert physical units (centimeters, millimeters, inches) into digital pixels (px) based on the image resolution (DPI/PPI).

What is DPI?

DPI (Dots Per Inch) or PPI (Pixels Per Inch) determines the density of pixels in an image.

72 DPI: Standard for web screens (monitors). Images load faster but shouldn't be printed.
300 DPI: Standard for high-quality printing (flyers, business cards, photos).

Conversion Formulas

If you want to calculate pixels manually, here are the formulas used by designers:

Conversion	Formula
Inches to Pixels	`Pixels = Inches × DPI`
CM to Pixels	`Pixels = (CM × DPI) ÷ 2.54`
MM to Pixels	`Pixels = (MM × DPI) ÷ 25.4`

Common Print Resolutions

Use this quick reference guide for common paper sizes at 300 DPI:

A4 Paper (21 x 29.7 cm): 2480 x 3508 px
Letter (8.5 x 11 in): 2550 x 3300 px
4x6 Photo (4 x 6 in): 1200 x 1800 px