How to Calculate Image DPI

Calculating image DPI takes two numbers: the pixel dimension and the physical print size.

Step by step

1. Find the pixel width, for example 3000 pixels.
2. Decide the print width in inches, for example 10 inches.
3. Divide: 3000 / 10 = 300 DPI.

If your print size is in centimeters, divide by 2.54 first to get inches. A 25.4 cm print width is 10 inches.

Worked examples

• 6000 × 4000 px printed 20 × 13.33 inches = 300 DPI.
• 1920 × 1080 px printed 10 inches wide = 192 DPI — fine for a poster, soft for a close-up photo print.
• The same 1920 px image printed 6.4 inches wide = 300 DPI.

Common mistake

Do not use the DPI number stored in the file as the answer. That metadata may be missing, wrong, or set for a different print size. Always calculate from pixels and your intended size.

Try it: DPI Calculator · Pixels to Inches