Calculate camera-sensor pixel pitch or estimate sensor resolution, with axis sampling, crop factor and diffraction references. The display mode calculates physical pixel pitch and PPI from the active screen diagonal and pixel dimensions.

Calculate horizontal and vertical sensor sampling pitch.

Use matching active physical dimensions and pixel counts. Sensor presets are reference sizes; verify the actual active area. Sampling and diffraction context do not guarantee resolved image detail.

Pixel Size Formula

For a display with square pixels, the formula below gives physical pixel pitch from the active display diagonal. The diagonal resolution is DR = √(W² + H²), where W and H are the horizontal and vertical pixel counts.

For a sensor, horizontal pitch is 1000 × active width (mm) / horizontal pixels, and vertical pitch is 1000 × active height (mm) / vertical pixels, giving micrometers. Use dimensions and pixel counts for the same active area. The megapixel mode uses the image width:height ratio, which is different from the shape of an individual pixel.

PS = (DS / DR) × 25.4

Variables:

  • PS is the pixel size (millimeters)
  • DS is the diagonal size of the display (inches)
  • DR is the diagonal resolution of the display (pixels)
  • 25.4 is the conversion factor from inches to millimeters

To calculate the pixel size, divide the diagonal size of the display by the diagonal resolution and then convert the result from inches to millimeters by multiplying by 25.4.

What is Pixel Size?

Pixel pitch is the physical spacing of the pixel grid on a display or camera sensor. Smaller pitch means more pixels per unit length, but does not by itself guarantee sharper images or better camera resolution. The display-diagonal mode assumes square pixels; sensor modes show horizontal and vertical pitch separately. Sensor Nyquist and 550 nm Airy comparisons are sampling and ideal-optics references, not guarantees of image quality.

How to Calculate Pixel Size?

The following steps outline how to calculate the Pixel Size.

  1. First, determine the resolution width (W) and resolution height (H) of the display in pixels.
  2. Next, determine the diagonal size (DS) of the display in inches.
  3. Calculate the diagonal resolution (DR) using the formula: DR = √(W² + H²).
  4. Use the pixel size formula: PS = (DS / DR) * 25.4.
  5. Finally, calculate the Pixel Size (PS) in millimeters.
  6. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Resolution Width (W) = 1920 pixels

Resolution Height (H) = 1080 pixels

Diagonal Size (DS) = 24 inches

With square pixels, DR = √(1920² + 1080²) ≈ 2202.907 pixels. The pitch is (24 / 2202.907) × 25.4 ≈ 0.276725 mm, equivalent to about 91.788 pixels per inch. Select the display-diagonal mode to reproduce this example.