File size isn't what Unity says it is

Hi there

I just checked my editor logs for the file size and its only meant to be 3.8MB, however the .exe and .apk files I export are ~11MB and ~8MB respectively.
Why and how do I fix this?

Here is an example from my editor logs:

Textures 27.0 kb 0.7%
Meshes 0.0 kb 0.0%
Animations 0.0 kb 0.0%
Sounds 0.0 kb 0.0%
Shaders 42.2 kb 1.1%
Other Assets 0.8 kb 0.0%
Levels 14.4 kb 0.4%
Scripts 11.8 kb 0.3%
Included DLLs 3.7 mb 97.1%
File headers 16.3 kb 0.4%
Complete size 3.8 mb 100.0%

Someone on the forums had this issues previously, see the end post where they describe the fix(rebuilding each scene(shutter)).

Unity Forums - Reducing APK Size - Editor Log vs Final Output

The size your editor shows is the size of all your assets together.
When you build it into an exe or apk, unity will also add the unity player and perhaps some .net library files. There is no way to fix this.