Account deletion is done from inside the App itself. Follow these steps:
Note: calculation results that only ever existed on your device (anything you never saved while signed in, or used before ever signing in) are separate local app data — uninstalling the App, or clearing the App's storage in your phone's Settings, removes that.
If you no longer have the App installed or can't complete the in-app steps, email support.rankpur@gmail.com from the email address on your account and we'll process the deletion manually after verifying it's really you.