DPI Calculator
Calculate image DPI/PPI from pixel dimensions and print size, or calculate print dimensions from pixels and DPI. No image upload needed.
How to use the DPI Calculator
- Calculate DPI — enter the image's pixel dimensions and the physical print size. The calculator returns horizontal, vertical, and average DPI.
- Calculate Print Size — enter the image's pixel dimensions and a target DPI. The calculator returns the maximum print size in inches, centimeters, and millimeters.
- No image upload is needed — this is a pure math calculator.
What is DPI / PPI?
DPI (dots per inch) and PPI (pixels per inch) describe the density of a printed or displayed image. The higher the DPI, the more detail is packed into each inch of print. A 300 DPI print looks crisp; a 72 DPI print at the same physical size will appear pixelated. The relationship is simple: DPI = pixels ÷ inches.
Common DPI values
Privacy — runs in your browser
All calculations run locally. No images or data are uploaded. No signup required.
Frequently Asked Questions
Is DPI the same as PPI?
Technically no — PPI (pixels per inch) refers to digital screens and image files, while DPI (dots per inch) refers to printer output. In practice, the terms are often used interchangeably when discussing print-quality requirements for image files.
What DPI do I need for a 4×6 photo print from a phone?
For a sharp 4×6 print at 300 DPI you need at least 1200×1800 pixels (4 × 300 = 1200, 6 × 300 = 1800). Most modern smartphones capture 12+ MP images, so they comfortably exceed this requirement.
Can I increase DPI without losing quality?
No — DPI is a function of how many pixels you have divided by the print size. Increasing the DPI setting in image software without adding real pixel data is called upsampling, which interpolates (guesses) new pixels and typically reduces sharpness.