PPI Calculator (Pixel Density)

How to Calculate PPI

PPI (pixels per inch) tells you how tightly pixels are packed on a screen. Here's the formula:

1. Find the diagonal in pixels: √(width² + height²)
2. Divide by the diagonal size in inches: PPI = diagonal pixels ÷ diagonal inches

Example: a 24-inch Full HD monitor (1920 × 1080):

• √(1920² + 1080²) = 2203 pixels on the diagonal
• 2203 ÷ 24 = 91.8 PPI

The calculator above does this instantly and also shows the dot pitch and the real width and height of the screen.

PPI of Common Screens

What Is a Good PPI?

It depends on how far away you sit:

• Desktop monitors (about 2 ft away): 90–110 PPI looks fine. 140+ looks very sharp.
• Laptops (about 1.5 ft): 140+ PPI gives crisp text.
• Phones (about 1 ft): 300+ PPI is so dense your eye can't see single pixels.
• TVs (6+ ft): Even 40–80 PPI looks sharp from the couch.

Higher PPI means sharper text and images. But it also means everything looks smaller unless your system scales it up.

PPI vs DPI

PPI measures pixels on a screen or in a digital image. DPI measures ink dots from a printer. People often use them as the same thing, especially for image files. Read the full explanation in What is DPI?

What Is Dot Pitch?

Dot pitch is the distance between the centers of two pixels, in millimeters. A smaller dot pitch means a denser, sharper screen. It's simply 25.4 ÷ PPI.