All screen test tools

    PPI Calculator for Monitor & Phone Pixel Density

    Calculate screen PPI, pixels per cm, pixel pitch and physical dimensions from resolution and diagonal size. Compare two monitors or phones with manual inputs.

    • PPI, PPCM and pixel pitch
    • Inches and centimeters
    • Compare two displays

    Calculate screen PPI, pixel pitch and visible size

    Enter the display’s specifications. Values below are calculated from your inputs, not detected hardware measurements.

    Display A

    Fill a common resolution

    Calculated results

    Pixels per inch (PPI)
    108.79
    Pixels per centimeter (PPCM)
    42.83
    Pixel pitch (mm)
    0.2335 mm
    Total pixels (MP)
    3.686
    Visible width × height
    59.77 × 33.62 cm 23.53 × 13.24 in
    Visible diagonal
    27 in · 68.58 cm

    PPI = √(width² + height²) ÷ diagonal in inches · PPCM = PPI ÷ 2.54 · pixel pitch = 25.4 ÷ PPI mm.

    How to use

    1. Enter the display’s native horizontal and vertical pixel counts and its visible diagonal, excluding the bezel.
    2. Choose inches or centimeters. Results update only when every input is valid.
    3. Add a second display to compare density and physical size. Keep the stated specifications handy; this tool does not detect them.

    What to keep in mind

    Calculations assume square pixels and the entered visible diagonal. Curved-screen specifications can use different measurement conventions. PPI does not measure color accuracy, text rendering, perceived sharpness or subpixel layout. Browser CSS pixels and devicePixelRatio are not your panel’s physical density.

    Questions

    How is screen PPI calculated?

    Divide the pixel diagonal, √(width² + height²), by the physical diagonal in inches. A 27-inch 2560 × 1440 screen is about 108.79 PPI. Pixel pitch is 25.4 ÷ PPI in millimeters.

    Does higher PPI always mean a better screen?

    Higher PPI means smaller pixels at the same physical size. Viewing distance, scaling, panel structure and your task also affect perceived detail. This calculator does not rate overall display quality.

    Can my browser detect the real screen size or PPI?

    Not reliably. Browser dimensions and scaling describe a software coordinate system. Enter the resolution and visible diagonal from your device’s specifications or measurements.

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