๐จ๏ธ Print Resolution Converter
Convert DPI (dots per inch), a common print resolution unit, into dots per centimeter or dots per millimeter in real time. Useful for checking foreign print specs or design software settings.
How to use
- Enter a value into any resolution unit field (dpi, dpcm, or dpmm).
- The converted values appear instantly in the other unit fields.
How the calculation works
DPI (dots per inch) is how many dots are placed along one inch (25.4 mm). Since an inch is 2.54 cm, dots per centimetre (dpcm) is DPI รท 2.54 and dots per millimetre (dpmm) is DPI รท 25.4. What matters when printing an image is the relationship between its pixel count and the print size. Print size in inches = pixels รท DPI, so the pixels you need = print size in inches ร DPI. Commercial printing commonly targets around 300โ350 DPI, roughly the density at which individual dots cannot be distinguished at a normal reading distance of about 30 cm. Posters and signs viewed from further away can use much lower resolutions without looking coarse. The right resolution depends on viewing distance.
Worked example
Converting 300 DPI Per cm: 300 รท 2.54 โ 118.1 dots Per mm: 300 รท 25.4 โ 11.8 dots Pixels needed to print A4 (210 ร 297 mm) at 350 DPI Width: 210 รท 25.4 ร 350 โ 2,894 px Height: 297 รท 25.4 ร 350 โ 4,093 px So roughly 2,900 ร 4,100 pixels, about 12 megapixels.
Things to be aware of
- Raising the DPI setting does not add pixels. If the source image is small, a higher DPI only makes the print smaller.
- DPI and PPI are strictly different concepts, but they are often used interchangeably in practice.
- Recommended resolutions vary between printers; check the specification before sending files.
- For images shown on screen, the DPI setting has no effect on display size.
FAQ
What's a good resolution for print?
300 dpi is a commonly recommended baseline for typical commercial printing, though the ideal value depends on the print type and viewing distance.
What's the difference between DPI and PPI?
DPI (dots per inch) technically refers to print dot density, while PPI (pixels per inch) refers to screen or image pixel density โ though in practice the two terms are often used interchangeably.
Can this calculate the relationship between pixel count and print size?
This tool only converts resolution units. To relate pixel count and print size, use: pixel count รท DPI = size in inches.