About the Pixels to CM / Inches Converter
This pixels to cm converter turns a pixel measurement into real-world size — centimeters, millimeters, inches and typographic points — at the resolution you choose. It also works in reverse: enter a physical size in cm, mm, inches or points and it tells you how many pixels you need at that DPI. A table shows the same measurement at the five most common resolutions so you can compare screen and print sizes in one glance.
It is handy for photographers checking how large an image will print, designers setting up print documents from screen mock-ups, and anyone filling in a form that asks for a photo "3.5 cm wide at 300 DPI". Remember that pixels have no physical size on their own — the DPI (dots per inch) or PPI (pixels per inch) setting is what links them to centimeters.
The default of 96 DPI matches the CSS reference pixel used by web browsers (1 in = 96 px). Print shops usually want 300 DPI for photos and 150 DPI for large posters viewed from a distance.
With the default inputs, the centimeters is 50.8 cm. Change any value above to recalculate instantly.
How to use the pixels to cm / inches converter
- 1Enter the measurement you want to convert.
- 2Choose its unit — pixels, cm, mm, inches or points.
- 3Set the resolution in DPI (96 for web, 300 for photo prints).
- 4Read the converted sizes and compare common DPIs in the table.
Formula and method
A pixel only gets a physical size once you decide how many pixels fit in one inch — the DPI (dots per inch) or PPI (pixels per inch). Dividing the pixel count by the DPI gives inches; the inch is defined as exactly 2.54 cm (25.4 mm), and a typographic point is exactly 1/72 inch. Going the other way, a physical size is converted to inches and multiplied by the DPI to get the pixel count.
On the web, CSS fixes the reference pixel at 96 per inch, so 1 cm is always about 37.8 CSS px regardless of the physical screen. Printed output uses the DPI stored with the image or chosen in the print dialog.
- px
- Number of pixels
- DPI
- Dots (pixels) per inch
- 2.54
- Centimeters per inch (exact)
- 72
- Points per inch (exact)
Worked examples
1920 px at the web standard 96 DPI
1920 ÷ 96 = 20 inches, and 20 × 2.54 = 50.8 cm (508 mm). In points that is 20 × 72 = 1,440 pt.
Print size of a 3000 px photo at 300 DPI
At 300 DPI, 3000 pixels cover 3000 ÷ 300 = 10 inches, exactly 25.4 cm — about the long side of an 8 × 10 in print.
Pixels needed for a 3.5 cm passport photo at 600 DPI
3.5 cm ÷ 2.54 = 1.378 inches; × 600 DPI = 826.77, so you need at least 827 pixels across. At 600 DPI there are 600 ÷ 2.54 ≈ 236.22 pixels per centimeter.
Frequently asked questions
How many pixels are in 1 cm?+
It depends on the resolution. At 96 DPI (the CSS web standard) 1 cm ≈ 37.8 px; at 72 DPI it is 28.35 px; at 300 DPI it is 118.11 px. The formula is pixels per cm = DPI ÷ 2.54.
What is the difference between DPI and PPI?+
PPI (pixels per inch) describes a digital image or screen, while DPI (dots per inch) strictly describes printer dots. In everyday use, including in image editors and this converter, the two are used interchangeably for pixels per inch.
What DPI should I use for printing?+
300 DPI is the standard for photos and documents viewed at arm’s length. Posters and banners viewed from further away look fine at 100–150 DPI. Screen-only images do not need a DPI setting at all.
Why is a CSS pixel 1/96 of an inch?+
The CSS specification defines an absolute inch as 96 reference pixels so that layouts look consistent across devices. On high-density screens one CSS pixel is drawn with several physical pixels, so it is not literally 1/96 inch on your monitor.
How big will my photo print?+
Divide the pixel width and height by the print DPI. A 6000 × 4000 px photo at 300 DPI prints at 20 × 13.33 inches (50.8 × 33.9 cm). Lower the DPI and the print gets larger but softer.