Image Print Size Calculator

The Image Print Size Calculator tells you exactly how large a digital image will print at a given resolution, and works in reverse to tell you how many pixels you need for a target print size. It converts between pixels, inches, centimeters and millimeters using nothing more than your image's pixel dimensions and a DPI (dots per inch) value.

The math behind print size and DPI

Digital images are measured in pixels; printed photos are measured in physical units. DPI (dots per inch, often used interchangeably with PPI, pixels per inch) is the bridge between the two. The core formula is simple:

• Print size (inches) = pixels ÷ DPI
• Centimeters = inches × 2.54
• Millimeters = inches × 25.4

For example, a 3000 × 2000 px image printed at 300 DPI comes out at 10 × 6.67 inches, or 25.4 × 16.93 cm. Drop the DPI to 150 and the same file prints twice as large (20 × 13.33 inches) but with half the detail per inch. This calculator always derives centimeters and millimeters from the raw pixel-and-DPI math, so rounding never accumulates across units.

How to use it

1. Choose a mode. Pixels to Print Size takes your image's pixel width and height and shows the physical print dimensions. Print Size to Pixels Needed takes a desired physical size and tells you the minimum pixel dimensions required.
2. Enter the width and height. In print-to-pixels mode, pick your unit (inches, centimeters or millimeters).
3. Set the DPI / PPI. Leave it at 300 for standard photo prints, or use one of the common presets below.
4. Read the results table — print size in inches, centimeters and millimeters, plus megapixels and orientation.

Everything runs instantly in your browser; no image is uploaded and no data leaves your device.

What DPI should I use for printing photos?

• 300 DPI is the standard for high-quality photo prints and anything viewed up close (books, magazines, greeting cards).
• 150 DPI is acceptable for draft prints or images seen from a short distance.
• 72 DPI is the classic screen/web resolution — fine for on-screen use, too low for quality prints.
• 600 DPI and above is used for fine-art reproduction and line art where crisp edges matter.

Large prints viewed from a distance (posters, banners) can go well below 300 DPI, because the viewer never gets close enough to see individual dots.

DPI vs PPI — are they the same?

For this calculation, yes. PPI describes pixels in a digital image, while DPI technically describes ink dots a printer lays down. In everyday photo-printing they're used interchangeably, and the pixels-to-inches math is identical either way.

Why do I get more pixels than expected in reverse mode?

When solving for pixels needed, the result is rounded up to the nearest whole pixel so the print never comes out under-resolved. Asking for a 21 × 29.7 cm (A4) print at 300 DPI, for instance, returns 2481 × 3508 px.

How big can I print my photo?

Divide each pixel dimension by your target DPI. A 24-megapixel camera (roughly 6000 × 4000 px) prints a sharp 20 × 13.3 inches at 300 DPI, or a very large 40 × 26.7 inches at a poster-friendly 150 DPI.