Question 1

What is PPI vs DPI?

Accepted Answer

PPI (Pixels Per Inch) measures digital display sharpness — the number of pixels packed into one inch of a screen. DPI (Dots Per Inch) originally referred to printed dots but is often used interchangeably with PPI today. A 1080p 24″ monitor has about 92 PPI, while a 4K 27″ display has around 163 PPI.

Question 2

How do I calculate PPI?

Accepted Answer

PPI = √(horizontalPixels² + verticalPixels²) / diagonalInches. For a 1920×1080 monitor with a 24″ diagonal: √(1920² + 1080²) / 24 = √(3,686,400 + 1,166,400) / 24 = √4,852,800 / 24 ≈ 92 PPI.

Question 3

Why does PPI matter?

Accepted Answer

PPI determines how sharp text and images look. Higher PPI means individual pixels become invisible at normal viewing distance. Apple calls displays above ~220 PPI 'Retina' because the pixels can no longer be seen. For design work, photo editing and reading comfort, 100+ PPI is recommended.

Question 4

What is a good PPI for a phone?

Accepted Answer

Most modern phones have 400-500+ PPI. The iPhone 15 Pro Max has 460 PPI, the Samsung Galaxy S24 Ultra has 501 PPI. Anything above 300 PPI is generally considered sharp at typical phone-holding distances.

Dot Pitch

Physical Width

Physical Height

Aspect Ratio

Total Pixels

Sharpness