# What is the difference between pixel pitch and pixel density?

This site already has a question around what is pixel density, but it doesn't mention pixel pitch at all. I am wondering what the relationship is, and what is important about the relationship to photographers today.

Not to foil the answers from others, but this fun equation is what spurred the question:

pixel pitch = 1/sqrt((pixel density per cm^2)/(10000^2))

I have no idea really what the above equation means, or even if it is accurate. I found it at this thread at dpreview.com.

• I sometimes see pixel pitch referred to as the "size of one pixel". Sorry I do not know if this fits any scientific definition. But if it does, pixel pitch is simply a measurement of size. Dec 28, 2011 at 7:05
• Pixel pitch is the size of one pixel + the size of the gap between adjacent pixels. Dec 28, 2011 at 10:27
• Here is a simple formula for pitch in microns: pixel_pitch = (sensor_width / pixels_per_row) * 1000. So, in the case of the 1D X, which has 5184 pixels per row in a 35mm format, pitch = (36mm / 5184) * 1000 = 0.0069444mm * 1000um/mm = 6.95um. Pixel density could be measured per millimeter, per centimeter, per inch...doesn't really matter...it is basically the pitch per distance (or better, per area, so pitch squared). So, no, pixel pitch and pixel density are not exactly the same, although they are related. Feb 27, 2013 at 19:41