PPI Calculator

Knowing that a television is "4K" tells you absolutely nothing about how sharp the final image will look. Resolution (4K) simply means the TV contains 8,294,400 pixels. The critical factor is how tightly those pixels are packed together—a metric known as PPI.

The Pythagorean Diagonal

Because screens are universally marketed by their diagonal length (e.g., a "65-inch TV" or a "6-inch Phone"), we first have to calculate how many pixels exist precisely along that diagonal line. We do this using standard high-school geometry (a² + b² = c²).

Dividing by Physical Space

Once you have the diagonal pixel count (a massive number), you simply divide it by the real-world physical diagonal of the screen measured in inches:

Why PPI Matters for Monitors vs. TVs

• Smartphones: Because you hold a phone 10-14 inches from your face, they require incredibly high density (usually 400+ PPI) to look smooth.
• Desktop Monitors: Sitting 2 to 3 feet back on a desk, standard pixel densities sit comfortably between 109 PPI (1080p on 22") and 163 PPI (4K on 27").
• Televisions: Sitting 10 feet back on a couch, your eyes cannot physically resolve high detail. A massive 65-inch 4K TV only has ~68 PPI, yet it still looks perfect from the sofa.