OhMyCalc

Image Resolution Calculator

Calculate DPI, megapixels, and estimated file size for an image at a given print size. Essential for photographers and print designers.

How to Use the Image Resolution Calculator

  1. Enter image width and height in pixels.
  2. Enter the desired print width in inches.
  3. Click Calculate to get DPI, megapixels, and file size.

使用例

計算式

DPI = Width (px) / Print Width (inches). Megapixels = Width × Height / 1,000,000. File size ≈ Width × Height × 3 bytes.

よくある質問

What DPI is good for print?
300 DPI is the standard for high-quality print. 150 DPI is acceptable for large-format prints viewed from a distance.
What is a megapixel?
One megapixel equals one million pixels. A 3000×2000 image has 6 megapixels.
Why is the file size estimate approximate?
The estimate assumes uncompressed RGB. JPEG, PNG, and other formats compress differently, resulting in smaller files.