Why do I need to free up way more space than the app requires?

[Android Central Question]

I am trying to download an app that requires 15mb of space. When I try to download it, it says I need to free up 300 something megabytes. Wtf is going on? Nobody ever answers me on forums so I'm not expecting a speedy response, but if someone is nice enough to help, can you please shed some light on this situation? Thank you so much.

 

[chanchan05]

I am trying to download an app that requires 15mb of space. When I try to download it, it says I need to free up 300 something megabytes. Wtf is going on? Nobody ever answers me on forums so I'm not expecting a speedy response, but if someone is nice enough to help, can you please shed some light on this situation? Thank you so much.

Because the app installer itself might only be 15mb, but additional data needed from servers will increase that as well as unpacking of the data. Also, Android by design will not let you go down below 500mb of available space because that space is required for the temp files apps create while running (deleted once the app is exited).

One example of the unpacking increase is the game War robots. The installer is 400mb, but installed it unpacks to 600mb. For additional data downloads, Hearthstone is an example. The installer is around 800mb, but the resources (game textures etc) push it to 3GB on installing.

 

[Rukbat]

And you have to have both the packed version (the .apk file, which is really just a .zip file with a different extension) and the unpacked version on the phone at the same time. If the developer is nice, he'll have the unpacked version immediately delete the .apk file, so that's all the space you need, but most developers leave that as the last thing, in case the installation doesn't go as planned (so you don't have to download the .apk file again).

The 500MB or so that you have to keep free is for files that Android and Linux (the operating system that Android runs on - the "kernel") use for themselves. In addition, there may be a certain amount of space the developer knows the app will use, so that's added to the amount of free storage you'll need to install the app. So a 15MB file may well need 300MB (plus 500MB for the system) free to install. (Android won't run very well with just 300MB free.)