Image Resolution Calculator
Pixels, print size, and DPI are linked by a single definition: DPI is the number of pixels packed into one inch of print. This calculator uses that to answer the everyday questions photographers and designers face. Enter your image's pixel dimensions and a printing DPI to see the print size in inches and the total megapixels. Enter a target print width to see the DPI you would actually achieve, so you can tell at a glance whether an image is large enough for a given print at the quality you need.
Image resolution formula
Print width (in) = pixel width / DPI
Print height (in) = pixel height / DPI
Megapixels = pixel width * pixel height / 1,000,000
DPI at target width = pixel width / target print width
DPI means pixels per inch, so dividing pixels by DPI gives inches. Megapixels are the total pixel count in millions. The DPI you achieve at a chosen print width tells you whether the image has enough resolution.
Resolution context
- DPI (dots per inch) for digital images is equivalent to pixels per inch.
- 300 DPI is a common target for sharp photo prints viewed up close.
- Large-format prints viewed from a distance can use lower DPI acceptably.
- Megapixels measure total resolution, not aspect ratio or print quality alone.
- Enlarging beyond the native pixel count reduces effective DPI and sharpness.
Image resolution: frequently asked questions
How do I work out print size from pixels and DPI?
Divide the pixel width by the DPI to get the print width in inches, and the pixel height by the DPI for the print height. For example, a 3,000 by 2,400 pixel image at 300 DPI prints at 10 by 8 inches.
What DPI do I need for a quality print?
A common standard for sharp photo prints is 300 DPI, while large prints viewed from a distance can use fewer. Enter the DPI your print process requires; this calculator does not assume one, because the right value depends on the medium and viewing distance.
How are megapixels calculated?
Megapixels are the total pixel count divided by one million. Multiply pixel width by pixel height to get total pixels, then divide by 1,000,000. A 3,000 by 2,400 image has 7,200,000 pixels, or 7.2 megapixels.
What DPI will I get at a target print size?
Divide the pixel width by the desired print width in inches to get the achievable DPI. If that DPI is below your quality threshold, the image is too small for that print size at full quality.
Are these calculations exact?
Yes. They are exact definitions: DPI is dots (pixels) per inch, so print size equals pixels divided by DPI, and megapixels are total pixels divided by one million. There are no estimated constants.
Official sources
- Library of Congress: Sustainability of Digital Formats (resolution).
- National Institute of Standards and Technology: Length unit definitions (inch).
Reviewed by the CalculatorHub team, edited by James Graham, 16 June 2026. See our methodology.