Work out pixel to centimetre instantly with clear inputs, formula shown and shareable results.
Pixels only have a physical size once a resolution is specified: length in inches is pixels divided by dpi. At the CSS default of 96 dpi, 1920 pixels is 20 inches or 50.8 cm; at 300 dpi print resolution the same pixel count is only 16.3 cm. That is why images must be sized in pixels for a target dpi.
Physical length
inches = pixels / dpi
Metric
cm = inches x 2.54
It was the nominal resolution of early Windows displays and became the CSS reference, so 1 CSS pixel is defined as 1/96 inch.
At 300 dpi, 2480 by 3508 pixels. Below about 200 dpi the pixel structure becomes visible at reading distance.