@Mosfar
@sh.itjust.worksYou can use the search bar for quick calculations. That doesn’t escuses Apple from adding an calculator app on iPad! Most calculator apps have ads or are paid
Like I said, I only do this once a year, other washes are done just with a pressure washer and a foam canon, sometimes when the car gets really dirty I use a mitt wash with shampoo after the foam canon.
I use this guide made by ChrisFix on YouTube and it doesn’t require much effort after the first wash. I only “deep clean” once a year