Apk size vs Installed app size

Hello everybody. My APK size is about 20MB I have set device filter to ARMv7 and Stripping level to Strip byte code. When I install my app on device app size is 50MB. Please can somebody explain me why this happens and advice me how can I reduce size of installed app.


APK file is essentially a zip file. It stands for Android Package Kit. You can test this theory by opening the APK in any established compression program (7zip etc.)