How the three values connect
Print sharpness depends on packing enough pixels into each printed inch. The relationship is simple: pixels equal DPI times inches, where DPI is dots (here, pixels) per inch.
Because the three quantities are tied together, fixing any two sets the third. Pick what you want to solve for and supply the others.
- Print size = pixels divided by DPI.
- Pixels = DPI multiplied by print size.
- DPI = pixels divided by print size.
Using the result
Solve for print size to learn the largest dimension an image can fill at a target DPI. Solve for DPI to see how dense an existing image would print at a chosen size.
If the DPI you get is well below your target, the print will look soft. Either print smaller or start from a higher-resolution image.
Picking a DPI target
The right DPI depends on viewing distance. Items held close need more detail than a poster seen across a room.
- About 300 DPI for photo prints and anything inspected up close.
- Around 150 DPI is often fine for large prints viewed from a distance.
- Screen images are described by total pixels, not DPI, so this is a print measure.
Common mistakes
Enlarging a small image in software adds pixels by guessing, which does not add real detail. The figure here assumes the pixels you enter are genuine.
Remember this works per dimension. Apply it separately to width and height when checking a full print.
Formula
pixels = dpi × inches; inches = pixels ÷ dpi; dpi = pixels ÷ inchesFrequently asked questions
- What DPI is good for printing?
- 300 DPI is the common target for sharp photo prints; 150 DPI can be acceptable for large prints viewed from a distance.