DPI vs PPI
Pixels per inch vs DPI is a distinction worth knowing: PPI describes pixels in an image or on a display, DPI describes the dots a printer lays down. For preparing a file they behave identically — but the difference is real, and it matters in two specific cases.
Leave the height blank to work from the width alone.
The strict definitions
PPI — pixels per inch — is a property of a digital raster: how many image pixels occupy each inch of a display, or of a print at a given size.
DPI — dots per inch — is a property of a printing device: how many individual ink or toner dots the hardware can place per inch of paper.
An inkjet rated at 2400 DPI does not want a 2400 PPI image. It uses many small dots of a few ink colours to simulate one continuous-tone pixel, a process called halftoning.
Why the terms are used interchangeably
When a print shop asks for "300 DPI artwork" they mean 300 pixels per inch at the final trim size. The industry adopted DPI as shorthand before desktop publishing made PPI the more accurate word, and the habit stuck.
For the purposes of sizing a file, treating the request as PPI gives exactly the right answer: pixels = inches × 300.
Where the difference genuinely matters
Three situations reward keeping the terms apart:
- Line art and text scans, where the printer’s own dot resolution decides how cleanly a hard edge reproduces. Scanning at 600–1200 PPI visibly beats 300.
- Screen printing and large-format output, where the device’s own dot structure sets a ceiling. Sending more pixels than it can resolve gains nothing visible and only slows the RIP.
- Display specifications, where a monitor has a PPI you can measure and no DPI at all.
Reference table
| PPI | DPI | |
|---|---|---|
| Measures | Image pixels per inch | Printer dots per inch |
| Applies to | Files and displays | Printing hardware |
| Typical values | 72, 96, 300, 460 | 600, 1200, 2400 |
| Set by | You, when sizing the file | The device |
| Used in the formula | inches = pixels ÷ PPI | Not used directly |
Frequently asked questions
Is DPI the same as PPI?
For preparing artwork, yes — both mean pixels per inch at the final size. Strictly, PPI counts image pixels and DPI counts printer ink dots.
How do I turn DPI into PPI?
No conversion is needed. DPI into PPI is a one-to-one relationship for artwork, so a file tagged 300 PPI already satisfies a request for 300 DPI.
Why does my printer say 2400 DPI?
That is the ink droplet resolution, not an image requirement. It still wants roughly a 300 PPI file; the extra dots are used to reproduce colour and tone.
Does a monitor have DPI?
Not really. A display has a pixel density measured in PPI. The term DPI is often applied loosely to screens, but there are no dots involved.