Pixels equal centimetres divided by 2.54, multiplied by the resolution in pixels per inch. A 10 cm edge printed at 300 PPI needs 10 ÷ 2.54 × 300 = 1181 pixels; on a screen using the CSS reference of 96 PPI, the same 10 cm is about 378 pixels.
A centimetre has no fixed pixel count. The answer depends on how densely the pixels are packed, so every conversion needs a resolution. Designers preparing print files, photographers checking whether an image is large enough for a 15 cm print, and developers turning a physical mock-up into CSS sizes all face the same sum. Enter a length and a resolution and the tool gives the whole-pixel count, the unrounded value, the length in inches, the pixel density per centimetre and, for comparison, the count at 300 PPI, the usual photo-print standard. One limit: a monitor's real pixel density varies by model, so a 96 PPI result tells you the CSS size, not how many centimetres the element will measure on a particular screen.
Type the physical size in centimetres, such as 21 for the width of an A4 sheet.
Use 300 PPI for photo print, 150 for posters seen from a distance, or 96 for CSS screen units.
The headline is rounded to whole pixels; the exact value and the working are listed below it.
Result Pixels: 96
Exact pixel value: 96
Length in inches: 1
Pixels per centimetre: 37.8
Pixels needed at 300 PPI: 300
One inch at the CSS reference resolution is exactly 96 pixels, the figure browsers use for physical units.
Result Pixels: 1,181
Exact pixel value: 1,181.1
Length in inches: 3.937
Pixels per centimetre: 118.11
Pixels needed at 300 PPI: 1,181
10 ÷ 2.54 = 3.937 in, times 300 gives 1181.1, so a 10 cm print edge needs about 1181 pixels.
Result Pixels: 1,240
Exact pixel value: 1,240.16
Length in inches: 8.2677
Pixels per centimetre: 59.06
Pixels needed at 300 PPI: 2,480
21 ÷ 2.54 × 150 = 1240.2, the pixel width of an A4 page scanned or exported at 150 PPI.
px = (cm ÷ 2.54) × PPI
cm2.54PPIpxResolution is quoted per inch, so the length is first turned into inches using the exact international definition of 2.54 cm per inch. Multiplying by the pixel density gives the pixel count. Images can only hold whole pixels, so the result is rounded to the nearest integer; the unrounded figure is kept so you can see how close it was.
It depends on resolution. At 96 PPI one centimetre is about 37.8 pixels, at 300 PPI about 118.1 pixels, and at 72 PPI about 28.3 pixels.
The CSS specification defines a reference pixel so that 1in equals 96px and 1cm equals about 37.8px. Browsers map that unit to the device, so physical CSS units rarely match a ruler exactly.
300 PPI is the common target for prints viewed at arm's length. Large posters seen from a few metres away often look fine at 150 PPI or lower, because the eye cannot resolve finer detail at that distance.
Not strictly. PPI counts image pixels per inch, while DPI counts ink dots a printer lays down. Many programs label the image setting DPI anyway, and for this conversion you enter the pixel figure.
Convert the width and the height separately with the same resolution. A 15 by 10 cm print at 300 PPI needs 1772 by 1181 pixels.
Only if resampling is switched on. With resampling off, the editor changes the print size and keeps the pixel count, which is the same relationship this formula describes.
Using this tool in an assignment, article or report? Copy a citation, or a link for your website.
Tools Directory Editorial Team. (2026, October 27). CM to Pixel. Tools Directory. Retrieved October 27, 2026, from https://tools.milunir.com/photography/image-size-and-print/cm-to-pixel/
Tools Directory Editorial Team. “CM to Pixel.” Tools Directory, 27 Oct. 2026, https://tools.milunir.com/photography/image-size-and-print/cm-to-pixel/. Accessed 27 Oct. 2026.
Tools Directory Editorial Team. “CM to Pixel.” Tools Directory. Last modified October 27, 2026. Accessed October 27, 2026. https://tools.milunir.com/photography/image-size-and-print/cm-to-pixel/.
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