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DPI Calculator: Work Out DPI, Print Size or Pixels

Know two of the three numbers, get the third. Pixels and print size give the DPI. Pixels and DPI give the print size. Print size and DPI give the pixels you need.

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Pixels = print size in inches x DPI. 1 inch = 2.54 cm. When the print and the image have a different shape, the lower DPI is the real one: the rest of the image is cropped.

How to calculate DPI

Divide the pixels by the inches. A 3000 pixel wide image printed 10 inches wide has 300 DPI (dots per inch). Do it for both sides. If the two numbers differ, the image and the print have a different shape. The lower number is the real DPI after cropping.

The same formula works the other two ways. Print size in inches = pixels / DPI. Pixels needed = inches x DPI. For centimetres, divide by 2.54 first to get inches.

Pixels needed for common print sizes

Print sizeAt 300 DPIAt 150 DPI
4 x 6 in1200 x 1800600 x 900
5 x 7 in1500 x 2100750 x 1050
8 x 10 in2400 x 30001200 x 1500
11 x 14 in3300 x 42001650 x 2100
16 x 20 in4800 x 60002400 x 3000
18 x 24 in5400 x 72002700 x 3600
24 x 36 in7200 x 108003600 x 5400
A4 (21 x 29.7 cm)2481 x 35081241 x 1754

Which DPI should you use?

300 DPI is the usual target for photo prints, art prints and printables that people look at up close. 150 DPI is often fine for big posters seen from a few feet away. Your print shop or print-on-demand service has the final word, so check its file guide.

A higher DPI number in the file does not add detail. Only more pixels do. If the calculator says your image is too small for the print, you need a bigger source file or an upscaler. Not sure what DPI your file has now? Drop it into the DPI checker.

Selling printables? Our guides on how to sell digital art and how to sell on Etsy cover the next steps.

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