1. Build and Run the App on Simulator .

2. Open the Finder on your Mac and press Cmd + Shift + G to open the "Go to Folder" dialog.

3. Enter path ~/Library/Developer/CoreSimulator/Devices -> This show Devices folder

4. Inside the Devices folder, you'll see a list of folders named with UUIDs. Each of these represents a simulator instance.

5. Navigate to data/Containers/Bundle/Application. There you see application type file and the size.

NOTE -> This give basic idea of app Size . For Know actual size we need .ipa file(Using apple developer account).

Like in my case my project size is 381.8 MB(which include 10+ pod). and By using above method It show size is 82.2 MB . But when I get .ipa file the my actual app size is 29.7 MB.