Explainer1 min readUpdated June 29, 2026

What is DPI and image resolution?

Short answer

Resolution is the number of pixels in an image, like 1920x1080. DPI (dots per inch) describes how densely those pixels are printed on paper. On a screen, DPI is mostly irrelevant; what matters is the pixel dimensions.

Resolution: how many pixels

An image is a grid of pixels, and its resolution is that grid's size, such as 1920 by 1080. More pixels means more detail and a larger file. This is the number that actually determines how sharp an image looks on a screen.

DPI: how densely it prints

DPI, and the closely related PPI (pixels per inch), describe how those pixels are spread out when printed. At 300 DPI, 300 pixels fit in one printed inch. The same pixel image can print large and coarse at a low DPI or small and crisp at a high DPI.

1200 pixels at 300 DPI  =  4 inches printed
1200 pixels at 150 DPI  =  8 inches printed

Pixels, DPI, and print size

DPI does not change screen qualityScreens render by pixels, not inches, so changing only the DPI tag does not make an image look better online. For the web, resize the pixel dimensions instead.

Try it: Image InfoInspect an image's pixel dimensions and details locally.Open tool

References

Questions

Is 300 DPI always required?

300 DPI is a common target for quality print, but it only matters for printing. For screens, the pixel dimensions are what count, not the DPI value.

What is the difference between DPI and PPI?

PPI (pixels per inch) refers to pixels in a digital image or display, while DPI (dots per inch) originally refers to printer dots. In everyday use the terms are often used interchangeably.

Do these tools upload my images?

No. Utilumo's image tools decode, edit, and export pictures inside the browser tab. The files are never uploaded or stored on a server.