Thanks very much to IndySusan and TaxGuyBill for their answers. I am not able to determine the correct approach, you both have well considered answers. So I came up with two spreadsheets so that I can figure it both ways. IndySusan method: mileage from time I turned on my Uber Driver app online. TaxGuyBill method: mileage at time I picked up my first rider. I personally am going to use the IndySusan method, but if I am audited, I have the ability to concede to them and use the TaxGuyBill method. The first form is a daily log you can print copies out of and put in your car to fill out each day. You enter the date, odometer when you went online, odometer at first pickup and odometer at time you went offline to return home. The two sheets I will share are shared, meaning you can make your own copy by clicking File - Make a copy, then using the copied version as your own, because you can't update mine. Daily Log form sheet is <a rel="nofollow" target="_blank" href="
https://docs.google.com/spreadsheets/d/1cbYCwyI7VqMseUCdqOvb5pwKhogL1AjcDixTFnDrnh4/edit?usp=sharing...>
Then you enter your dates and odometer readings, Uber Pay and Uber Miles on a cumulative Uber Log sheet, which calculates the IRS taxable earnings both ways, IndySusan method and TaxGuyBill method.
The Uber Log sheet is <a rel="nofollow" target="_blank" href="
https://docs.google.com/spreadsheets/d/1SW4M4u59mucteZFO1bWGJErH7NHmfx9EDgP4DluV5po/edit?usp=sharing...>
I hope these are helpful to fellow Uber drivers who are going to use the mileage deduction method.