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PPI Calculator

Calculate pixel density (PPI) from screen size and resolution. Compare two displays side by side — monitors, phones, tablets, TVs.

A Display A

Pixel Density
—
PPI
—

B Display B

Pixel Density
—
PPI
—

📊 Comparison

Display A
— PPI
Display B
— PPI
—

PPI Reference by Device Type

Desktop Monitor
90-150 PPI
arm's length
Laptop
120-230 PPI
closer viewing
Phone/Tablet
300-500+ PPI
handheld
TV
40-80 PPI
far viewing

About This Tool

Choosing between two monitors? Wondering if a 27" 4K is sharper than a 24" 1440p? This calculator tells you the exact pixel density (PPI) — the number that actually determines sharpness. Enter the screen diagonal and resolution for any display, and get the PPI instantly. Use the comparison mode to see two devices side by side — with a visual difference indicator and sharpness rating. The tool covers common presets for monitors, phones, tablets, and TVs. Higher PPI means sharper text and images. At typical viewing distances: 100+ PPI is good for monitors, 300+ PPI is "Retina" quality for phones. This calculator helps you make informed display choices based on real numbers, not marketing specs.

How to Use

1. Enter screen diagonal (inches) and resolution (width × height) for Display A 2. View the calculated PPI and sharpness rating 3. Optionally add Display B to compare side by side 4. Use presets for common devices (iPhone, MacBook, 4K monitor, etc.) 5. Check the visual comparison bar and % difference 6. Click "Copy Link" to share your comparison

Formula

PPI = √(width² + height²) ÷ diagonal Example: 27" monitor at 2560×1440 Diagonal pixels = √(2560² + 1440²) = 2937.3 PPI = 2937.3 ÷ 27 = 108.8 Reference PPI ranges: Desktop monitor (arm's length): 90-110 PPI standard, 140+ sharp Laptop (closer): 120-150 PPI standard, 200+ sharp Phone (handheld): 300+ PPI "Retina", 400+ very sharp TV (far viewing): 40-80 PPI typical

Frequently Asked Questions

What is PPI and why does it matter?
PPI (pixels per inch) measures how densely pixels are packed on a screen. Higher PPI means sharper text and images. A 100 PPI monitor looks fine at arm's length, but you'd see individual pixels on a 100 PPI phone held close to your face. Context matters — viewing distance determines what PPI you need.
What is a good PPI for a monitor?
For a desktop monitor at typical arm's length (~60-80 cm): 90-110 PPI is standard and comfortable. 110-140 PPI is sharp. 140+ PPI is very sharp (like 4K at 27" = 163 PPI). Going above 150 PPI on a desktop may require scaling, which can cause blurry apps.
What is Retina display PPI?
Apple's 'Retina' standard is ~300 PPI for phones (held at 10-12 inches) where individual pixels become invisible to the eye. For laptops/tablets held further away, Retina is ~220-260 PPI. It's a viewing-distance-adjusted threshold, not a fixed number.
Is 4K worth it on a 27 inch monitor?
27" 4K (3840×2160) = 163 PPI — noticeably sharper than 27" 1440p (109 PPI). Text is crisp and images are detailed. However, you'll likely need to use 125-150% scaling, which some apps handle poorly. Many prefer 32" for 4K (138 PPI) to use 100% scaling.
How do I calculate PPI manually?
First, find diagonal pixels: √(width² + height²). Then divide by screen diagonal in inches. For a 1920×1080 24" screen: √(1920² + 1080²) = 2203, then 2203 ÷ 24 = 91.8 PPI. This calculator does it automatically.
What PPI do phones have?
Modern smartphones typically have 400-500+ PPI. iPhone 15 Pro: 460 PPI. Samsung Galaxy S24: 416 PPI. Pixel 8: 428 PPI. These high densities ensure sharpness at close viewing distances. Anything above 300 PPI is considered 'Retina' quality for handheld devices.
Does higher PPI mean better display quality?
PPI measures sharpness/pixel density only. Display quality also depends on panel type (OLED, IPS, VA), color accuracy, contrast ratio, brightness, and response time. A 100 PPI OLED can look better than a 150 PPI cheap IPS panel. PPI is one factor among many.

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