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How to Calculate Image Resolution

What is Image Resolution?

Image resolution determines print size and quality. 300 DPI is the standard for professional print; 72–96 DPI suits screen display. This converts pixel dimensions to physical print sizes.

Formula

Megapixels = Width (px) × Height (px) / 1,000,000 | File size (MB) ≈ Megapixels × Bytes per pixel / 1,000,000

Step-by-Step Guide

  1. 1Print width (inches) = Pixel width / DPI
  2. 2Convert to cm: multiply by 2.54
  3. 3Megapixels = Width px × Height px / 1,000,000
  4. 4Enlarging beyond native DPI causes pixellation

Worked Examples

Input
4000 × 3000 pixels at 300 DPI
Result
13.3" × 10" print (33.9 × 25.4 cm); 12 MP image

Frequently Asked Questions

What is Image Resolution?

Image resolution determines print size and quality. 300 DPI is the standard for professional print; 72–96 DPI suits screen display

How accurate is the Image Resolution calculator?

The calculator uses the standard published formula for image resolution. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

What units does the Image Resolution calculator use?

This calculator works with centimetres, inches, watts. You can enter values in the units shown — the calculator handles all conversions internally.

What formula does the Image Resolution calculator use?

The core formula is: Print width (inches) = Pixel width / DPI. Each step in the calculation is shown so you can verify the result manually.

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