Megapixel Calculator

Megapixels are just width in pixels times height in pixels, divided by one million — this calculator does exactly that, then uses the same width and height to derive three practical numbers photographers actually need. Print sizes at 72, 150, and 300 DPI divide each pixel dimension by the DPI value to get inches, since DPI (dots per inch) defines how many pixels are packed into each printed inch: 300 DPI is the standard for sharp, close-viewing prints, 150 DPI is acceptable for larger prints viewed from a normal distance, and 72 DPI (historically a screen-resolution default) produces much larger dimensions but at a print quality too coarse for anything meant to be viewed up close. File size estimates come from three different assumptions about bytes per pixel: uncompressed 8-bit RGB assumes exactly 3 bytes per pixel (one byte each for red, green, blue channels) divided by 1024² to convert to megabytes; the RAW estimate uses roughly 1.75 bytes per pixel as a rough stand-in for 14-bit RAW sensor data with typical compression and file overhead (real RAW file sizes vary meaningfully by camera manufacturer and compression scheme, so treat this as an approximation, not a spec); and the JPEG estimate simply divides the uncompressed size by 10, reflecting JPEG's typical (but highly content-dependent) compression ratio.

The print quality assessment is a straightforward megapixel-count lookup table, from "thumbnails only" below 2MP up through "gallery prints, large format" at 50MP and above. It's worth knowing this only accounts for resolution, not other real limits on print quality — lens sharpness, sensor noise, and camera shake all affect how large you can genuinely print an image, so this calculator's guidance is a ceiling based on pixel count alone, not a guarantee that any given file will look good at that size.