Screen PPI Calculator
Calculate pixel density, pixel pitch, aspect ratio and the viewing distance where pixels blend for any monitor, TV or phone screen.
In short
Calculate pixel density, pixel pitch, aspect ratio and the viewing distance where pixels blend for any monitor, TV or phone screen.
Formula: PPI = √(width² + height²) ÷ diagonal. Pixel pitch = 25.4 ÷ PPI mm. Distance where one pixel spans 1 arcminute = 1 ÷ (PPI × tan(1/60°)).
What this calculator does
Calculate pixel density, pixel pitch, aspect ratio and the viewing distance where pixels blend for any monitor, TV or phone screen.
You enter horizontal pixels, vertical pixels, screen diagonal and viewing distance (optional), and the screen ppi calculator shows the answer along with the working, so you can check it or try other numbers.
The page shows the formula, a numeric worked example, and the assumptions that affect this math calculation.
Inputs and what they mean
- Horizontal pixels
- — number value.
- Vertical pixels
- — number value.
- Screen diagonal
- — number value.
- Viewing distance (optional)
- — number value.
How to use it
- Enter each value in the unit shown next to the box (use the unit converter first if your numbers are in other units).
- Check the breakdown to see every intermediate step.
- Read the limitations before relying on the result.
Formula
1 arcminute (1/60 of a degree) is the conventional resolution of 20/20 vision.
PPI = √(width² + height²) ÷ diagonal. Pixel pitch = 25.4 ÷ PPI mm. Distance where one pixel spans 1 arcminute = 1 ÷ (PPI × tan(1/60°)).
Inputs used: Horizontal pixels, Vertical pixels, Screen diagonal, Viewing distance (optional).
Worked example
27-inch 2560 × 1440
- Diagonal pixels = √(6,553,600 + 2,073,600) ≈ 2,937.2.
- PPI = 2,937.2 ÷ 27 ≈ 108.79.
- Distance = 1 ÷ (108.79 × 0.00029089) ≈ 31.6 in.
Reading the result
The headline figure is the main answer. Any breakdown underneath shows the parts that make it up, so you can check the working and see what changes when you adjust an input.
Limitations and assumptions
- Assumes square pixels.
- Visual acuity varies between people and with contrast and content.
- Does not account for scaling or subpixel layout.
- Geometric estimates. The 1-arcminute limit describes typical 20/20 acuity; individual eyesight differs.
- The result depends on the values you enter for this screen ppi calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.
Reference: Wolfram MathWorld
Last reviewed:
Common questions
Is higher PPI always better?
Only until pixels are too small to see at your distance. Beyond that, extra resolution is hard to notice.
What is the 1-arcminute rule?
Typical 20/20 vision resolves detail about 1/60 of a degree wide, so smaller pixels blend together.
Does it work in centimetres?
Enter the diagonal and distance in inches; the blending distance is also shown in centimetres.
How do I use the Screen PPI Calculator?
Enter the required values for Horizontal pixels, Vertical pixels, Screen diagonal, Viewing distance (optional). The calculator applies the formula on this page and shows the main result with any supporting breakdown so you can check the arithmetic.
What formula does the Screen PPI Calculator use?
PPI = √(width² + height²) ÷ diagonal. Pixel pitch = 25.4 ÷ PPI mm. Distance where one pixel spans 1 arcminute = 1 ÷ (PPI × tan(1/60°)). The visible formula section above lists the calculation path and the edge cases the page handles, so the result can be checked without relying on the form alone.
Can the Screen PPI Calculator be used for exact decisions?
Use it as a calculation aid, not as a substitute for checking the underlying rule, contract, policy, or professional advice that applies to your situation. When a result depends on local rules, personal details, prices, or dates, enter those values yourself and confirm them before acting.
Sources
Method based on Wolfram MathWorld.
Cite this page
Free Calculator. (2026, November 3). Screen PPI Calculator. https://freecalculator.tech/tools/screen-ppi-calculator
"Screen PPI Calculator." Free Calculator, 3 Nov. 2026, https://freecalculator.tech/tools/screen-ppi-calculator.
Screen PPI Calculator — Free Calculator, https://freecalculator.tech/tools/screen-ppi-calculator
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