Updated July 9, 2026
What DPI actually measures
DPI stands for dots per inch, the count of individual ink dots a printer lays down within each inch of paper. Pack more dots into that inch and detail gets finer, gradients get smoother, edges get crisper. At 300 DPI, a printer lays 300 dots across every horizontal inch and 300 down every vertical inch, which adds up to 1,200 x 1,800 dots on a 4x6, or about 2.16 million total.
How Is DPI Calculated
DPI comes from dividing the pixel count an image supplies by the number of inches it is being printed across. A file with 1,800 pixels on its long edge, printed at 6 inches, works out to 300 DPI on that edge: 1,800 divided by 6. Shrink the print size with the same pixel count and DPI climbs; enlarge it and DPI falls, since the same pixels are stretched across more paper.
Run your own image through it
The DPI Calculator takes a pixel count and a print size and returns the exact DPI, no arithmetic required.
Is 600 DPI higher than 300 DPI?
Yes, 600 DPI places twice as many dots per inch as 300. For most photo prints at normal viewing distances, 300 DPI looks indistinguishable from 600 to the naked eye. The higher setting earns its keep on very fine detail: textured fine art prints, technical drawings, anything examined six inches from a face.
Is 600 DPI or 1200 DPI better?
1200 DPI is technically finer, but at a foot or more the eye cannot separate 300 from 600 DPI, let alone 600 from 1200. The gain from 1200 DPI shows up in line art, crisp text, and prints examined under a loupe, not in standard photo output.
Related calculators
The Print Size Calculator shows the largest sharp print a given image can produce, and the Required Resolution Calculator runs the same math starting from your target print size instead of your pixel count.
Quick questions on DPI
Is 600 DPI higher than 300 DPI?
Yes, twice as many dots per inch. For most photo printing, 300 DPI is already sharp enough at normal viewing distance; 600 DPI helps mainly on very detailed subjects.
What is DPI on a mouse?
Mouse DPI measures cursor sensitivity, how far the pointer travels per inch of physical mouse movement. It shares a name with printer DPI by coincidence and has no bearing on print quality.
Is 600 DPI or 1200 DPI better for printing?
1200 DPI is technically finer, but at normal photo viewing distances most people cannot tell 300 from 600, let alone 600 from 1200. It earns its keep on line art and text.
What is 300 DPI in pixels?
300 pixels for every inch of output. A 4x6 print needs 1,200 x 1,800 pixels; a 5x7 needs 1,500 x 2,100.