About

A common misconception in digital design is that a "pixel" is a fixed physical unit. In reality, a pixel's physical size depends entirely on the resolution (PPI - Pixels Per Inch) of the display or printer. A 1-inch line contains 96 pixels on a standard Windows screen, but 300 pixels on a high-quality print.

This tool allows designers and developers to convert physical measurements (inches, millimeters) into pixel values by explicitly defining the target PPI context. It solves the frustration of "blurry" images or misaligned layouts by calculating the exact pixel dimensions required for specific media, whether it's a Retina display (high PPI) or a billboard (low PPI).

Formulas

The conversion is a function of density:

px = Length_inch × PPI

Standard PPI Contexts:

96 PPI: CSS Reference Pixel (Web Standard).
72 PPI: Legacy Mac / Typography points (1 pt ≈ 1 px).
300 PPI: Standard Print Quality.

Reference Data

Physical Size	Web (96 PPI)	Retina (192 PPI)	Print (300 PPI)
1 Inch	96 px	192 px	300 px
1 Centimeter	38 px	76 px	118 px
A4 Width (210mm)	794 px	1587 px	2480 px
Business Card (3.5")	336 px	672 px	1050 px
1 Point (pt)	1.33 px	2.66 px	4.16 px

Frequently Asked Questions

The W3C CSS specification defines the reference pixel such that 96px equals 1 physical inch. This is the standard for web development, regardless of the actual hardware capabilities of the screen.

No. 3D printing resolution is usually measured in microns (layer height), not PPI. This tool is for 2D surface rasterization (Screens and Inkjet/Laser printers).

For web images, stick to 72 or 96 PPI, but ensure the pixel dimensions (width x height) are large enough for the display container. For print, 300 PPI is the industry minimum for crisp text and lines.