Calculators
DPI Calculator
DPI links the digital world to the printed one. On its own an image has no physical size, only pixels; DPI decides how many of those pixels are squeezed into each printed inch, and therefore how large and how sharp the print will be.
Enter any two of pixels, inches and DPI, and the third is calculated for you.
Pixels to print size
Print size (inches)
10.00 × 6.67 in
Print size (cm)
25.4 × 16.9 cm
Pixels needed for a print
Pixels required at 300 DPI
2400 × 3000 px
How to use this tool
- 1Enter the pixel dimensions of your image, or the print size you need.
- 2Set the DPI you intend to print at, typically 300 for photos.
- 3Read the calculated result.
- 4If the pixel count is short, do not upscale; reshoot or re-export from the original.
Standard DPI values
Commercial photo printing and magazines use 300 DPI. Large-format posters viewed from a distance are fine at 150 DPI, and billboards often go far lower because nobody stands close. Screens are not measured in DPI at all: a web image is described by its pixel dimensions, and 72 DPI is a historical artefact with no practical meaning online.
A worked example
You want an A4 print, 8.27 × 11.69 inches, at 300 DPI. Multiply: 8.27 × 300 = 2481 px and 11.69 × 300 = 3507 px. Your file needs to be at least 2481×3507 pixels. A 12 MP phone photo at 4000×3000 comfortably covers it.
Upscaling does not add detail
Enlarging a small image to reach a pixel target invents pixels by interpolation. The print will look soft. It is nearly always better to print slightly smaller at full resolution than larger from an upscaled file.
Frequently Asked Questions
Is DPI the same as PPI?
In everyday use, yes. Strictly, PPI describes pixels per inch in a digital file and DPI describes ink dots per inch on paper, and printers place several dots per pixel.
Does changing DPI change file size?
No. DPI is a metadata tag. Only the pixel dimensions affect how many bytes the file holds.
What DPI should web images use?
It does not matter. Browsers ignore the DPI field entirely and use pixel dimensions.
Can I print a 72 DPI image?
Yes. Ignore the tag and check the pixel dimensions against the size you want to print.