Image DPI checker

How to check an image

1. Press Choose an image and pick a photo or graphic. Any format your browser can open works.
2. Pick a Print size: 10 × 15 cm (4 × 6 in), 13 × 18 cm (5 × 7 in), 20 × 30 cm (8 × 12 in), A4, US Letter, A3, or Custom in centimetres.
3. Read Effective PPI at this size and the message below the buttons. Try other sizes to find the largest that still works for you.

Reading the numbers

• Pixels and Megapixels: the image's actual size, which is what limits print sharpness.
• Effective PPI: pixels divided by the print size in inches. The page assumes the image fills the whole print size, cropping if its shape differs, and picks the orientation that fits best — so the value is on the safe side.
• 300 ppi or more: the usual guideline for photos viewed up close. 150 to 300 ppi: usually fine for prints viewed at arm's length or further, though fine detail may look softer. Below 150 ppi: likely to look soft or pixelated at that size.
• Largest print at 300 / 150 ppi: the print size, in centimetres, at which the image reaches those resolutions.

These values are common guidelines, not rules. Posters and banners viewed from a distance are often printed at lower resolutions without looking soft.

DPI in the file and other limits

• The DPI or PPI number stored in an image file is only a label. Changing it does not add detail; only the pixel count and the print size decide the effective resolution.
• Enlarging an image in software adds pixels but not detail, so a higher PPI from upscaling does not guarantee a sharper print.
• Focus, noise and heavy JPEG compression affect print quality as much as resolution, and the checker cannot judge them.
• Printer DPI, the number of ink dots per inch, is a different thing from image PPI.

To check how your printer reproduces colour before printing photos, use the colour printer test page; to check that it prints at true size, the printer alignment test page.