But seriously, as Yoop mentioned, it is pretty easy to calculate.
I have learned on this forum and in my experience that my grist ratio is dialed in for my system.
I sometimes make small changes dependent on recipe, but I shoot for around 1.33 and unless I miss mash temps and have to add more, I hover around that ratio.
I do the same as Yooper, except that I use a mash thickness of 1 qt per lb, because I usually make EPAs. (The thick mash is traditional for the beers that I make.)