Print size calculator
Enter pixels and DPI, get the print size.
How big can I print a photo?
Divide the pixel dimensions by the print resolution in dots per inch. A 6,000 × 4,000 pixel photo at 300 DPI prints at 20 × 13.3 inches.
What DPI should I use?
It depends on the print and viewing distance — photo labs often ask for about 300; large posters seen from farther away can use less. Check what your printer or lab recommends.
How do I find how many pixels I need?
Multiply the print size by the DPI: an 8 × 10 inch print at 300 DPI needs 2,400 × 3,000 pixels.
What are megapixels?
Width × height in pixels ÷ 1,000,000. The 6,000 × 4,000 photo is 24 megapixels.
Is DPI the same as PPI?
People often use them interchangeably. Strictly, PPI is pixels per inch in the image and DPI is ink dots per inch from the printer.
Worked example: one photo at three resolutions
The 6,000 × 4,000 pixel photo has 24 megapixels. At 300 DPI it prints 20.0 × 13.3 inches, at 200 DPI 30.0 × 20.0 inches and at 150 DPI 40.0 × 26.7 inches. The number of pixels does not change; only how widely they are spread. In centimeters, multiply inches by 2.54: the 300 DPI print is 50.8 × 33.9 cm. A smaller photo of 3,000 × 2,000 pixels (6 megapixels) reaches 10 × 6.7 inches at 300 DPI.
What if the photo is stretched to a bigger size?
The effective resolution is the pixels divided by the inches. If the 3,000-pixel-wide photo is printed 20 inches wide, it works out to 150 pixels per inch, half of 300. Enlarging a file in software adds pixels but no new detail, so the print looks like the lower number. As a guide, here are the pixel dimensions that give 300 DPI at common sizes: 4 × 6 in: 1200 × 1800; 5 × 7 in: 1500 × 2100; 8 × 10 in: 2400 × 3000; 11 × 14 in: 3300 × 4200; 16 × 20 in: 4800 × 6000. Ask the lab or printer whether they accept a lower figure for large or distant prints.
Why does my photo not fit an 8 × 10 print?
Photo shapes differ from paper shapes. A 6,000 × 4,000 photo has a 3:2 shape, while 8 × 10 is 4:5, so something must be cropped. To fill the 10-inch side with the full 4,000-pixel height, the width needs only 5000 pixels, so 1000 pixels (17% of the width) are cropped away. The 4,000 pixels across 8 inches are then 500 per inch, well above 300. Check the crop before ordering so that a face or an edge does not get cut.
Common mistakes with print size
Trusting the DPI number stored in a file: it is only a label and does not change how many pixels the image has. Comparing megapixels with print size directly: shape and viewing distance matter as well as the count. Forgetting the crop when the photo’s proportions differ from the paper. Mixing up screen and print: an image shown at 72 or 96 pixels per inch on a screen can still print well if it has enough pixels. And ignoring that borders or bleed reduce the visible area: ask the lab how much of the edge is trimmed.
Sources and related calculators
Sources: the definition of the inch (1 in = 25.4 mm exactly) and the relation pixels = inches × pixels per inch; the DPI choice for your print is the lab’s or printer’s own guidance. Related: PPI calculator, aspect ratio calculator and length converter.