I used to do it but I haven\'t done it in a while and i\'ve added to my game. Don\'t remember where on Xcode I can check the approximate app store size of my app.
I
To find out what's the size of the file that user will download from the App Store, you need to do the following.
Export your archive for testing outside the store.
Select “Export for specific devices” and choose “All compatible device variants” from the pop-up menu.
Select "Rebuild from bitcode." EDIT: this step doesn't exist since as late as Xcode 9.4.1.
For more information take a look at apple docs.