Tecnología

PPI Calculator: Screen Pixel Density

Calculate your screen's PPI (pixels per inch) from resolution and diagonal size. Check if it's Retina quality (300+ PPI), with a reference table of common phones, laptops and monitors.

🗓️ Updated June 2026 Reviewed by Martín Rodríguez

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Reviewed by: Martín Rodríguez (editorial policy ) · Last reviewed: Jun 20, 2026

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PPI (pixels per inch) tells you how sharp a screen really is — and it's not the same as resolution. A 1080p phone looks crisp while a 1080p 27-inch monitor looks chunky, because the same pixels are spread over a much larger area. Enter your screen's width and height in pixels plus its diagonal in inches, and this calculator returns the exact PPI plus whether it reaches Retina-class sharpness (300+ PPI). Includes a reference chart of common phones, laptops and monitors so you can compare before you buy.

When to use this calculator

Calculate the PPI of any phone, laptop or monitor from its specs
Check whether a display reaches Retina-class sharpness (300+ PPI)
Compare two monitors with the same resolution but different sizes
Decide between a 1440p and 4K monitor at a given screen size
Verify a spec sheet's claimed pixel density before buying

PPI Reference: Common Screens by Device Type

Device	Resolution	Diagonal	PPI	Retina (300+ PPI)?
iPhone 15 Pro	2556×1179	6.1"	461	✓
Samsung Galaxy S24	2340×1080	6.2"	416	✓
iPad Pro 11"	2388×1668	11.0"	264	✗
MacBook Pro 14"	3024×1964	14.2"	254	✗
15.6" laptop (4K)	3840×2160	15.6"	282	✗
15.6" laptop (1080p)	1920×1080	15.6"	141	✗
24" monitor (1080p)	1920×1080	24"	92	✗
27" monitor (1080p)	1920×1080	27"	82	✗
27" monitor (1440p)	2560×1440	27"	109	✗
27" monitor (4K)	3840×2160	27"	163	✗
32" monitor (1440p)	2560×1440	32"	92	✗
32" monitor (4K)	3840×2160	32"	138	✗

Fuente: valores calculados con PPI = √(width² + height²) ÷ diagonal, según especificaciones oficiales de fabricante. Umbral Retina: 300 PPI (Apple, support.apple.com/en-us/HT202471).

How it works

How to calculate PPI (pixels per inch)

PPI measures how densely pixels are packed on a screen. The formula uses the screen's resolution in pixels and its physical diagonal in inches:

PPI = √(width² + height²) ÷ diagonal

The square root gives you the diagonal length in pixels; dividing by the diagonal in inches gives pixels per inch. For a 1920×1080 panel measuring 24 inches diagonally: √(1920² + 1080²) = 2,202.9 pixels, divided by 24 = 92 PPI.

PPI vs. resolution: why they're not the same

Resolution alone (e.g. "1080p") tells you nothing about sharpness — you also need the screen size. The same 1920×1080 looks razor-sharp on a 5-inch phone (≈440 PPI) and visibly blocky on a 27-inch monitor (≈82 PPI), because the pixels are spread over a much larger surface. PPI is the number that actually predicts how crisp text and images will look.

PPI reference table for common screens

Device	Resolution	Diagonal	PPI
iPhone 15 Pro	2556×1179	6.1"	461
Samsung Galaxy S24	2340×1080	6.2"	416
iPad Pro 11"	2388×1668	11.0"	264
MacBook Pro 14"	3024×1964	14.2"	254
15.6" laptop (4K)	3840×2160	15.6"	282
15.6" laptop (1080p)	1920×1080	15.6"	141
24" monitor (1080p)	1920×1080	24"	92
27" monitor (1080p)	1920×1080	27"	82
27" monitor (1440p)	2560×1440	27"	109
27" monitor (4K)	3840×2160	27"	163
32" monitor (4K)	3840×2160	32"	138
32" monitor (1440p)	2560×1440	32"	92

Sharpness benchmarks by device type

Smartphones & tablets: 300+ PPI — held close to the eye, so they need the highest density. Most flagship phones run 400–500 PPI.

Laptops: 200–300 PPI on high-end "Retina"/HiDPI panels; ~140 PPI on standard 1080p panels.

Desktop monitors: 90–110 PPI is typical and looks fine at arm's length. 4K at 27" (~163 PPI) is noticeably sharper.

TVs & very large displays: 40–80 PPI, but viewed from across a room so the lower density isn't visible.

What is a Retina display?

"Retina" is Apple's marketing term for a display dense enough that, at a normal viewing distance, a person with 20/20 vision can't resolve individual pixels. The often-quoted threshold is ~300 PPI for a phone held ~25–30 cm away, but the real cutoff depends on distance: a desktop monitor viewed from 60 cm only needs ~110–130 PPI to look equally "retina" because it's farther from your eyes. This calculator uses 300 PPI as the standard reference cutoff.

Important note

PPI describes pixel density only. Perceived sharpness also depends on viewing distance, panel type, subpixel layout (RGB vs. PenTile) and scaling settings (device pixel ratio). Use PPI as the primary comparison number, then weigh those factors.

Worked example: 24-inch 1080p monitor

Resolution 1920×1080, diagonal 24 inches

Diagonal in pixels = √(1920² + 1080²) = √4,852,800 = 2,202.9 px

PPI = 2,202.9 ÷ 24 = 91.8

≈ 92 PPI (standard desktop sharpness, well below the 300 PPI Retina threshold)

Frequently asked questions

How do I calculate PPI by hand?

Use PPI = √(width² + height²) ÷ diagonal. Square the horizontal and vertical pixel counts, add them, take the square root to get the diagonal in pixels, then divide by the diagonal screen size in inches. Example: 2560×1440 on a 27-inch monitor = √(2560²+1440²)/27 = 2937/27 ≈ 109 PPI.

What PPI is considered Retina or 'sharp'?

Roughly 300+ PPI for a phone held at normal reading distance. For laptops the practical sweet spot is 200–300 PPI, and for desktop monitors viewed from arm's length about 110–160 PPI already looks very crisp. Higher distance lowers the PPI you actually need.

What PPI does a 27-inch 4K monitor have?

A 27-inch 4K (3840×2160) monitor has about 163 PPI — clearly sharper than the ~82 PPI of a 27-inch 1080p monitor and the ~109 PPI of a 27-inch 1440p monitor.

What is the PPI of a 24-inch 1080p monitor?

About 92 PPI. 1920×1080 spread across a 24-inch diagonal gives √(1920²+1080²)/24 ≈ 91.8 PPI, the typical density of a standard desktop monitor.

Why does my 1080p phone look sharper than my 1080p monitor?

Because the same 1920×1080 pixels are packed into a much smaller screen on the phone. A 5-inch 1080p phone is around 440 PPI while a 24-inch 1080p monitor is only ~92 PPI — over four times denser, so the phone looks far crisper.

Is PPI the same as DPI?

Not exactly. PPI (pixels per inch) refers to screen pixel density; DPI (dots per inch) refers to printer dot density. People often use the terms interchangeably for screens, but technically DPI belongs to printing and PPI belongs to displays.

What is device pixel ratio (DPR) and how does it relate to PPI?

DPR is how the operating system maps logical CSS pixels to physical pixels. HiDPI screens use 2× or 3× DPR so interface elements stay a usable size on a very high-PPI panel. A 460 PPI phone at DPR 3 renders UI as if it were ~153 PPI while still drawing text with the full pixel detail.

Does higher PPI always mean a better screen?

No. Beyond the point where your eye can't see pixels at your viewing distance, extra PPI mostly costs more money and battery without a visible benefit. Panel quality, brightness, contrast and color accuracy often matter more than chasing the highest PPI number.

What PPI do I need for a gaming or office monitor?

For a desktop viewed at arm's length, 90–110 PPI (1440p at 27") is comfortable and 150–160 PPI (4K at 27") is excellent. Below ~80 PPI (1080p at 27" or larger) text starts to look soft and pixelated.

Sources & references

Methodology & trust

Editorial

Calculadora de tecnología revisada por el equipo editorial de Hacé Cuentas, contrastada con Apple — Retina display, displays & resolutions, según nuestra política editorial y metodología.

Updates

Última revisión: June 20, 2026. Los parámetros se verifican periódicamente con las fuentes citadas.

Privacy

Calculations run 100% in your browser. We do not store or transmit your data.

Limitations

Indicative results. For critical decisions, consult a professional.

📌 How to cite this calculator

Rodríguez, M. (2026). PPI Calculator: Screen Pixel Density. Hacé Cuentas. https://hacecuentas.com/screen-ppi-pixel-density

Contenido bajo licencia CC-BY 4.0 — reutilizable citando la fuente con enlace a Hacé Cuentas.

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