Work out print dimensions from pixels

A 3000×2400 photo at 300 DPI prints at exactly 10×8 inches — the px↔DPI↔size math, both directions.

Tools used in this guide

Print size calculator
Aspect ratio calculator
Image resizer

The job

Two opposite questions share one formula: how large will this image print at 300 DPI, and how many pixels does an A4 print need? Pixels ÷ DPI = inches.

Convert

Pick a direction, enter both axes and the DPI, and read the converted pair. Width and height are independent — lock the aspect yourself if it must hold.

300 DPI is photo-print standard; 150 is readable, 600 is for fine line art.
Inches ÷ 25.4 gives mm; the tool reports mm, cm, and inches together.

Worked example

A 2400×3000 px scan at 300 DPI prints at 8×10 in — 203×254 mm. Printing that file on A4 at the same DPI needs 2480×3508 px, which it does not have.

Where it stops

DPI range 1–2400. It converts dimensions only — it does not resample an image (use the image resizer), and print-quality labels are rough guidance, not a judgement of your file.