🖼 Image & Media

DPI & Print Size Calculator

Convert pixel dimensions and DPI to physical print size (cm/inch). A reference table lists common paper sizes such as A4 at 300 DPI. Everything stays in your browser.

Examples (click to try)
inches
cm
PaperSize (mm)300DPI (px)150DPI (px)
A4210 × 2972480 × 35081240 × 1754
A5148 × 2101748 × 2480874 × 1240
A6 (postcard)105 × 1481240 × 1748620 × 874
L (photo)89 × 1271051 × 1500526 × 750
Business card91 × 551075 × 650537 × 325

How to Use the DPI & Print Size Calculator

Enter your image's pixel count and the output DPI, or pick an example chip. Inches and cm update together, and the table below shows how many pixels common paper sizes need at each DPI. Handy for checking resolution before sending files to print.

Worked examples

  • 3000px @300DPI → prints up to 10.00 in (25.40 cm)
  • 2480px @300DPI → 8.27 in (21.00 cm) = exactly A4 width
  • 1024px @72DPI → 14.22 in (36.12 cm) = physical size at screen density
  • 1500px @150DPI → 10.00 in (25.40 cm) = the same 10 in would need 3000 px at 300 DPI

Before You Print

Use this as a quick preflight check for posters, flyers, photo prints and scanned images. A file can look large on screen but still be too small for high-quality print if the pixel count is low for the chosen DPI.

DPI Does Not Add Image Detail

Here DPI is an output-density assumption: it assigns a number of pixels to each printed inch. Changing only an image file's DPI metadata does not create pixels or detail. Printing the same pixel dimensions at a larger physical size lowers effective pixels per inch and can make the result look softer.

Required resolution depends on the print process, paper, viewing distance, and supplier, so follow the printer's specification instead of treating 300 DPI as universal. Check shape separately with the Aspect Ratio Calculator.

FAQ

Is my data sent to a server?
No. Everything runs in your browser; nothing is transmitted or stored externally.
What is the formula?
inches = pixels ÷ DPI; cm = inches × 2.54. Since 1 inch = 25.4 mm, you can also get mm = inches × 25.4.
What DPI should I print at?
Use about 300 DPI for normal prints, around 150 DPI for large posters viewed from a distance, and 72–96 DPI for screen display. For example, printing A4 at 300 DPI needs roughly 2480×3508 px.
What is the largest size I can print from my image?
Enter your pixel count and the target DPI (300 for print) to see the printable size in cm/inch. Example: 3000 px @ 300 DPI prints up to 10 inches (25.4 cm). Enlarging beyond that looks soft.
How many pixels do I need for A4?
A4 is 210×297 mm, and pixels = mm ÷ 25.4 × DPI. That is roughly 2480×3508 px at 300 DPI, or half that (about 1240×1754 px) at 150 DPI. Add bleed to all four sides when the printer asks for it — 3 mm is about 35 px at 300 DPI. The table on this page lists the common paper sizes.
Does changing the DPI field in an image editor make the file higher resolution?
No. DPI only states how many pixels to lay down per inch on output, so the amount of information stays the same unless the pixel count grows. Even resampling to more pixels only interpolates from what is already there, so real detail is not added. Check whether the original pixel count is sufficient before enlarging the print size.