What is the difference between “px”, “dp”, “dip” and “sp” on Android?

From the Android Developer Documentation:

1. px
   Pixels - corresponds to actual pixels on the screen.

2. in
   Inches - based on the physical size of the screen.
   1 Inch = 2.54 centimeters

3. mm
   Millimeters - based on the physical size of the screen.

4. pt
   Points - 1/72 of an inch based on the physical size of the screen.

5. dp or dip
   Density-independent Pixels - an abstract unit that is based on the physical density of the screen. These units are relative to a 160 dpi screen, so one dp is one pixel on a 160 dpi screen. The ratio of dp-to-pixel will change with the screen density, but not necessarily in direct proportion. Note: The compiler accepts both "dip" and "dp", though "dp" is more consistent with "sp".

6. sp
   Scale-independent Pixels - this is like the dp unit, but it is also scaled by the user's font size preference. It is recommend you use this unit when specifying font sizes, so they will be adjusted for both the screen density and user's preference.

More info can be also be found in the Google Design Documentation.

• answered 7 years ago
• Community  wiki

• answered 7 years ago
• Community  wiki

1) px Pixels - point per scale corresponds to actual pixels on the screen.

2) in Inches - based on the physical size of the screen.

3) mm Millimeters - based on the physical size of the screen.

4) pt Points - 1/72 of an inch based on the physical size of the screen.

5) dp Density - independent Pixels - an abstract unit that is based on the physical density of the screen. These units are relative to a 160 dpi screen, so one dp is one pixel on a 160 dpi screen. The ratio of dp-to-pixel will change with the screen density, but not necessarily in direct proportion. Note: The compiler accepts both dip and dp, though dp is more consistent with sp.

6) sp Scale-independent Pixels - this is like the dp unit, but it is also scaled by the user's font size preference. It is recommend you use this unit when specifying font sizes, so they will be adjusted for both the screen density and user's preference.

Take the example of two screens that are the same size but one has a screen density of 160 dpi (dots per inch, i.e. pixels per inch) and the other is 240 dpi.

                         Lower resolution   screen          Higher resolution, same size
Physical Width                      1.5 inches                        1.5 inches
Dots Per Inch (“dpi”)               160                               240
Pixels (=width*dpi)                 240                               360
Density (factor of baseline 160)    1.0                               1.5
Density-independent Pixels          240                               240
(“dip” or “dp” or “dps”)
Scale-independent pixels (“sip” or “sp”)    Depends on user font size settings  same

• answered 7 years ago
• Community  wiki