Pixels to cm chart: image sizes at 72, 150 and 300 DPI

A pixel count tells you how much detail an image has, not how big it is. The physical size appears only when you print it, and that depends on how many pixels you put in each inch: the DPI (strictly, PPI). The chart below takes common pixel widths and heights and gives the printed length in centimeters at 72, 96, 150 and 300 DPI.

The formula

cm = pixels ÷ DPI × 2.54. Pixels divided by DPI gives inches, and an inch is exactly 2.54 cm. Turned around, one centimeter holds DPI ÷ 2.54 pixels.

Pixels to centimeters at four DPI values

Pixels per centimeter

Which DPI to read

300 DPI is the usual target for photos and anything read up close. 150 DPI is fine for posters and prints viewed from a meter or more. 96 is the CSS pixel, which browsers define as 1/96 inch, so it is the number to use when a web layout needs a size in cm. 72 is the old default many programs still write into image files. It does not mean the image is low quality; it just gives a large printed size if nobody changes it. If you are going from a paper size to pixels instead, our print sizes in pixels at 300 DPI table does that direction.

Worked example: a 4000 × 3000 photo

A 12-megapixel phone photo is 4000 × 3000 pixels. At 300 DPI the width is 4000 ÷ 300 × 2.54 = 33.87 cm and the height is 25.40 cm. That is larger than an A4 sheet (21 × 29.7 cm) in both directions, so the photo fills A4 at full 300 DPI quality. Drop to 150 DPI for a wall poster and the same file reaches 67.7 × 50.8 cm.