Icon Reference

Pixel Densities

Android icons require five separate sizes for different screen pixel densities. Icons for lower resolution are created automatically from the baseline.

[table caption=”Pixel Densities” th=”false”]
mdpi (Baseline), 160 dpi,1×
hdpi:, 240 dpi,1.5×
xhdpi:, 320 dpi,2×
xxhdpi:, 490 dpi,3×
xxxhdpi:, 640 dpi, 4×
[/table]

Launcher icons

[table]
48 × 48 (mdpi)
72 × 72 (hdpi)
96 × 96 (xhdpi)
144 × 144 (xxhdpi)
192 × 192 (xxxhdpi)
512 × 512 (Google Play store)
[/table]

Action bar, Dialog & Tab icons

[table]
24 × 24 area in 32 × 32 (mdpi)
36 × 36 area in 48 × 48 (hdpi)
48 × 48 area in 64 × 64 (xhdpi)
72 × 72 area in 96 × 96 (xxhdpi)
96 × 96 area in 128 × 128 (xxxhdpi)
[/table]
These icons are used in the action bar menu. The first number is the size of the icon area, and the second is file size.

 

Small Contextual Icons

[table]
16 × 16 (mdpi)
24 × 24 (hdpi)
32 × 32 (xhdpi)
48 × 48 (xxhdpi)
64 × 64 (xxxhdpi)
[/table]
Small icons are used to surface actions and/or provide status for specific items. For example, in the Gmail app, each message has a star icon that marks the message as important.

 

Notification icons

These are used to represent application notifications in the status bar. They should be flat (no gradients), white and face-on perspective

[table]
22 × 22 area in 24 × 24 (mdpi)
33 × 33 area in 36 × 36 (hdpi)
44 × 44 area in 48 × 48 (xhdpi)
66 × 66 area in 72 × 72 (xxhdpi)
88 × 88 area in 96 × 96 (xxxhdpi)
[/table]

 

Taken from here