Simple DPI Calculator For 2026

What The DPI Calculator Works Out

• Maximum print size: pixels divided by the print resolution, in inches and centimetres. A 3000 x 2000 pixel image at the 300 DPI print-shop standard makes a 10 x 6.7 inch print (about 25 x 17 cm); the same file at 150 DPI stretches to twice that in each direction. DPI is only an instruction for how densely to lay the pixels down, so changing a file's DPI without resampling changes nothing except the intended print size.
• Megapixels: width times height in millions of pixels. A 12 MP phone photo (4000 x 3000) prints beautifully to 10 x 13 inches at 300 DPI and acceptably to A3, while heavy cropping spends those pixels fast.
• Fits which print: the largest standard size, from a 6 x 4 photo to A2, that the image fills at the chosen DPI in either orientation.
• Custom DPI (advanced): any resolution instead of the four presets, for example 240 DPI, which many labs accept as indistinguishable from 300, or 200 DPI for canvas prints.
• Target print size and effective DPI (advanced): pick a standard size (photo sizes, A5 to A0, canvases) or type a custom width and height in centimetres, and the calculator works backwards to the DPI your image would actually print at, with a verdict. 300 is right for anything read at arm's length, 150 is fine for posters viewed from a metre or two, and billboards run at 20 to 50 because nobody reads them from the pavement.
• Pixels needed for the target (advanced): the width and height in pixels the target size demands at your chosen DPI, and how far short the image falls. An A3 poster at 300 DPI needs roughly 4961 x 3508 pixels (17 MP), which is why licensing the large stock image matters and why a screenshot never survives printing.
• Bleed per edge (advanced): extra millimetres printers trim off (3 mm is standard for commercial print), added to the target size before the pixel requirement is worked out.
• Viewing distance (advanced): the eye resolves about one arcminute, so the DPI needed falls as you step back: about 340 DPI at 25 cm, 115 DPI at 75 cm and 43 DPI at 2 m. The card gives the DPI for your distance and the largest print the image can make while still looking sharp from there.
• Uncompressed file size (advanced): pixels times 3 bytes for 24-bit colour, the size of a TIFF or BMP master; a high-quality JPEG is roughly a tenth of it. Capture or license more pixels than the final print needs and downsample rather than up: upscaling software can invent plausible detail for modest enlargements, but the honest rule stands.
• Standard sizes table (advanced): the effective DPI and verdict for this image at every size from 6 x 4 inches to A0, alongside the pixels each would need at your chosen resolution.