Megapixel Print Size Calculator
The resolution of your camera sets a ceiling on how large you can print before detail breaks down. This calculator turns a megapixel count and an aspect ratio into pixel dimensions, then divides by your target DPI to give the largest print size in inches that holds that quality. Enter your camera's megapixels, the aspect ratio, and the DPI you want to print at to see the maximum print width and height.
Megapixel print formula
Total pixels = megapixels * 1,000,000
Long side px = sqrt(total * (long ratio / short ratio))
Short side px = total / long side px
Print inches = pixel side / target DPI
The aspect ratio fixes the shape; the megapixel count fixes the area. Dividing each pixel dimension by the DPI gives the print size that keeps that resolution.
Worked example
A 24 megapixel 3:2 image: total = 24,000,000 pixels. Long side = sqrt(24,000,000 * 1.5) = 6,000 pixels; short side = 24,000,000 / 6,000 = 4,000 pixels. At 300 DPI the print is 6,000 / 300 = 20.00 by 4,000 / 300 = 13.33 inches.
Megapixel print size: frequently asked questions
How big can I print from my megapixels?
First convert megapixels and aspect ratio to pixel width and height, then divide each by your target DPI to get the print size in inches. A 24 megapixel 3:2 image is about 6,000 by 4,000 pixels, which prints to 20 by 13.3 inches at 300 DPI.
How are pixel dimensions found from megapixels?
Total pixels = megapixels times 1,000,000. With an aspect ratio width:height, the long side equals the square root of (total pixels times ratio) and the short side equals total pixels divided by the long side. This calculator does that automatically.
What DPI should I use?
300 DPI is the usual standard for sharp prints viewed at arm's length. Larger prints viewed from farther away can drop to 150 DPI or less. Enter your target DPI to see how large you can print while keeping that resolution.
Sources
- NIST: Office of Weights and Measures (inch definition).
- The pixel-to-print arithmetic uses only the definitions of megapixel, aspect ratio, and DPI; no external figure is required.
Reviewed by the CalculatorHub team, edited by James Graham, 19 June 2026. See our methodology.