Print Size Calculator
How large a photo or image prints from its pixels at a DPI (PPI), how many pixels a print size needs at a DPI, and what DPI a print would have, in centimetres, millimetres and inches.
Result…
How it's calculated
Print size (in) = pixels ÷ DPI · cm = in × 2.54 Pixels needed = print size (in) × DPI, rounded up DPI = pixels ÷ print size (in)
A digital image has a fixed number of pixels; the DPI (strictly PPI, pixels per inch) says how many of them are laid along each inch of paper. Divide the pixels by the DPI for the print size in inches, and multiply by 2.54 for centimetres (an inch is exactly 25.4 mm). Turn it round to find the pixels a print needs, or divide the pixels by a print size to see the DPI it would have. When the image and the paper have different shapes, part of the image is cropped to fill the paper, or a border is left. Printers and labs advise different resolutions for different prints, and larger prints are usually seen from further away, so enter the DPI your printer recommends.
Your numbers, step by step
About the Print Size calculator
This print size calculator shows how big a photo can be printed and how sharp the print will be. Enter the image's width and height in pixels and a resolution in DPI (strictly PPI, pixels per inch), and it gives the print size in centimetres, millimetres and inches, with the megapixels and aspect ratio. Turn it round to find the pixels a print size needs at a chosen DPI, for example before buying a stock photo or scanning artwork. Or enter the pixels and a paper size to see the DPI the print would have, both when the image is cropped to fill the paper and when it fits whole with a border. Photographers, designers and anyone ordering prints can check their files before they send them. An inch is exactly 2.54 cm, and every division is shown with your numbers.
How to use it
- Choose what to “Work out”: “Print size”, “Pixels needed” or “DPI of a print”.
- Enter the “Image width” and “Image height” in pixels from the file's details.
- Enter the “Resolution” in DPI that your printer or lab recommends.
- For pixels or DPI, choose “Print size in” cm, mm or inches and enter the “Print width” and “Print height”.
- Read the size, the pixels or the DPI, and check the aspect ratio against the paper.
Worked example
A 6000 × 4000 pixel photo at 300 DPI prints at 6000 ÷ 300 = 20 in by 4000 ÷ 300 = 13.33 in, which is 50.8 × 33.87 cm. It has 24 megapixels and a 3:2 shape. A 30 × 20 cm print at 300 DPI needs 30 ÷ 2.54 × 300 = 3543.3, rounded up to 3,544 px, by 2,363 px. A 4000 × 3000 image on 15 × 10 cm paper has 677 DPI when it is cropped to fill the paper and 762 DPI when it fits whole with a border.
Updated
Questions people ask
How do I work out print size from pixels and DPI?
Divide the pixel width and height by the DPI to get inches, then multiply by 2.54 for centimetres. 3000 pixels at 300 DPI is 10 in, or 25.4 cm.
How many pixels do I need for an 8 × 10 inch print?
Convert the print size to inches and multiply by the DPI. An 8 × 10 in print at 300 DPI needs 2400 × 3000 pixels; for a metric size, divide the centimetres by 2.54 first.
Are DPI and PPI the same thing?
PPI counts the image's pixels per inch of print, while DPI strictly counts the ink dots a printer lays down, and a printer may use several dots for each pixel. In print-size settings the two words are used for the same number.
Why is part of my photo cut off when I print it?
The photo's aspect ratio doesn't match the paper's, so filling the paper crops the longer side. The aspect ratio calculator finds a crop that matches the paper.
What resolution does a print need to look sharp?
There is no single number: it depends on the printer, the paper and how far away the print is seen, and large prints are usually seen from further off. Ask your print lab what it recommends. The pixels per inch calculator does the same sum for screens.