Estimating total size

To get the closest approximate size on each platform, use the following
instructions.

Android

Follow the Google Play Console’s instructions for checking app download and
install sizes.

Produce an upload package for your application:

flutter build appbundle

Log into your Google Play Console. Upload your application binary by drag
dropping the .aab file.

View the application’s download and install size in the Android vitals ->
App size tab.

The download size is calculated based on an XXXHDPI (~640dpi) device on an
arm64-v8a architecture. Your end users’ download sizes may vary depending on
their hardware.

The top tab has a toggle for download size and install size. The page also
contains optimization tips further below.

iOS

Create an Xcode App Size Report.