Physical Pixels vs CSS Pixels vs Device Independent Pixels vs Density Independent Pixels vs PPI : <p>I am learning web development and I am having a hard time determining what is equivalent in all of this. </p>

<p>I know hardware pixels and physical pixels are the smallest unit, and that density independent pixels map to actual hardware pixels via a device pixel ratio and they are used to make the viewing experience more consistent.  Does this mean that the device independent pixels I'm seeing are the same thing?</p>

<p>Further, I read that the browser reports viewport width in CSS pixels, are these and DIPs the same thing? </p>

<p>I know that Pixels per inch are literal, they are the number of pixels in an inch, but how do they relate to DIPs? A totally separate measurement? When should I use that instead? </p>

<p>I hope this is an appropriate question, I am having issues mentally linking all of these concepts into one usable map, and didn't find any other question where they are all addressed at once. </p>
