When you need this conversion
You have a physical size, such as a flyer, a sticker or a photo print, and you need to create or export an image that fills it without looking soft. Design tools ask for pixel dimensions, so you convert the centimeters you were given into pixels at the resolution the output needs.
Picking a resolution
- 300 DPI for anything held in the hand: photos, flyers, business cards, packaging.
- 150 DPI for large posters and banners seen from a few meters away.
- 96 DPI when the “centimeters” are CSS centimeters on a web page. CSS defines 1 cm as 37.7953 px.
Worked approach for print
- Take the trimmed size, for example 10 × 15 cm.
- Add bleed if the design touches the edge: 10.6 × 15.6 cm.
- Convert at 300 DPI: 1252 × 1843 px (rounded up).
- Export at those dimensions and set the file’s DPI metadata to 300.
If you are going the other way, from an existing image to its printed size, use the pixels to centimeters converter.
Common mistakes
Designing at screen resolution for print. A 794 px wide A4 design is fine on screen, but printed at 300 DPI it only covers 6.7 cm.
Forgetting that CSS centimeters are not real centimeters on screen. Browsers treat 1 cm as 37.8 CSS pixels, but a phone or monitor will not show exactly 1 cm on a ruler. The mapping is exact on paper, not on glass.