Relation between dp - sp and PX

Question

I am not asking what is the difference between dp,sp and px.

I am designing a website based on google\'s new material design, all the measurements are in dp (for grid)

Answer 1

All are roughly equivalent for most use cases.

Source

To preserve the visible size of your UI on screens with different densities, you must design your UI using density-independent pixels (dp) as your unit of measurement. One dp is a virtual pixel unit that's roughly equal to one pixel on a medium-density screen (160dpi; the "baseline" density). Android translates this value to the appropriate number of real pixels for each other density.

For example, consider the two devices in figure 1. If you were to define a view to be "100px" wide, it will appear much larger on the device on the left. So you must instead use "100dp" to ensure it appears the same size on both screens.

When defining text sizes, however, you should instead use scalable pixels (sp) as your units (but never use sp for layout sizes). The sp unit is the same size as dp, by default, but it resizes based on the user's preferred text size.

Figure 1. Two screens of the same size may have a different number of pixels