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PPI/DPI Calculator Calculate pixel density (PPI/DPI) from screen resolution and physical size.

PPI/DPI Calculator illustration
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PPI/DPI Calculator

Calculate pixel density (PPI/DPI) from screen resolution and physical size.

1

Enter Resolution

Input screen width and height in pixels.

2

Enter Screen Size

Input the diagonal screen size in inches.

3

View Pixel Density

See PPI, dot pitch, physical dimensions, and total megapixels.

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What Is PPI/DPI Calculator?

The PPI/DPI Calculator determines the pixel density of any screen by computing Pixels Per Inch (PPI) from the display resolution and physical diagonal size. Higher PPI means sharper, more detailed images. The calculator also shows dot pitch (distance between pixels in mm), physical width and height in inches, and total megapixel count. Quick presets for common devices (iPhone, 1080p monitor, 4K monitor, iPad) make it easy to compare pixel densities across different screens.

Why Use PPI/DPI Calculator?

  • Calculates PPI from resolution and screen size
  • Shows dot pitch, physical dimensions, and megapixels
  • Quick presets for common devices
  • Compare pixel density across different displays

Common Use Cases

Display Shopping

Compare pixel density when choosing monitors or TVs.

Design Work

Understand how designs will appear at different pixel densities.

Print Preparation

Verify resolution meets print DPI requirements.

Device Comparison

Compare screen sharpness across phones, tablets, and monitors.

Technical Guide

PPI is calculated as: PPI = √(W² + H²) / D, where W and H are pixel dimensions and D is the diagonal in inches. Dot pitch = 25.4 / PPI (millimeters between pixel centers). Physical dimensions: Width(in) = W / PPI, Height(in) = H / PPI. Total pixels = W × H. For reference: typical viewing distances determine the minimum PPI needed to appear "sharp" — about 300 PPI for phones held at 10", 100+ PPI for monitors at 24", and 50+ PPI for TVs at 10 feet. Apple's "Retina" standard is approximately where individual pixels become indistinguishable at typical viewing distance.

Tips & Best Practices

  • 1
    PPI above 300 is considered "retina quality" for handheld devices
  • 2
    For desktop monitors at arm's length, 100+ PPI is generally sharp enough
  • 3
    Higher PPI means smaller UI elements unless scaling is applied
  • 4
    Print typically requires 300 DPI for sharp output

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Frequently Asked Questions

Q What is the difference between PPI and DPI?
PPI (Pixels Per Inch) refers to screen displays. DPI (Dots Per Inch) refers to printing. For screens, PPI and DPI are often used interchangeably.
Q What PPI is considered "good"?
For phones: 300+ PPI. For tablets: 200+ PPI. For desktop monitors: 100+ PPI. For TVs: 40+ PPI (viewed from distance).
Q Does higher PPI mean better?
Higher PPI means sharper images, but beyond a certain point (depending on viewing distance), the human eye cannot distinguish the difference.
Q What PPI do I need for printing?
Print typically requires 300 DPI for sharp results. 150 DPI is acceptable for large posters. Below 100 DPI will appear pixelated.
Q Why does my 4K TV have lower PPI than my phone?
Because TVs have much larger screens. A 55" 4K TV has ~80 PPI, while a 6" phone at 1080p has ~400 PPI. But TVs are viewed from farther away.

About This Tool

PPI/DPI Calculator is a free online tool by FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration or installation required.