Print Size From Megapixels Calculator
Find the largest sharp print your camera can make — pixel dimensions and print size at any DPI, from megapixels and aspect ratio.
How it works
Width px = √(megapixels × 10⁶ × aspect ratio) · Print inches = pixels ÷ DPI · cm = inches × 2.54
Print size is just the pixel count spread across a chosen density. Given the total pixels (megapixels × one million) and the aspect ratio, the width and height in pixels follow from geometry; dividing each by the print resolution converts pixels into inches. Higher DPI packs pixels tighter for a smaller, crisper print, while lower DPI stretches the same pixels into a bigger picture — fine for wall art viewed from a distance but soft in the hand.
Worked example
A 24 MP camera at 3:2 has 6000 × 4000 pixels. At 300 DPI that prints 6000 ÷ 300 = 20 in wide by 13.3 in tall; drop to 150 DPI for a large print and it doubles to 40 × 26.7 in.
Frequently asked questions
What DPI do I need for a good print?
300 DPI is the standard for prints viewed up close, like photo books and framed portraits. 150–200 DPI is fine for posters and canvases seen from a metre or more, and billboards use far less because viewers stand far away.
Does more megapixels always mean bigger prints?
For a fixed DPI, yes — pixel count sets the ceiling. But lens sharpness, focus and noise matter just as much; a clean 24 MP file often prints better than a soft 45 MP one.
What is the difference between DPI and PPI?
PPI (pixels per inch) describes the digital image, while DPI (dots per inch) describes the printer’s ink dots. In everyday photo printing the terms are used interchangeably, and this calculator treats them as the same.
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This calculator is for educational purposes. Double-check important results before acting on them.