I am tracking Germany's numbers I use this formula for rate of growth over 7 days
=(((day7-day1)*100)/day1)/10
My reasoning to wanting to calculate the R
I could also just do it daily but I think over 7 days is better, I think the incidence level concept is flawed, because trending in Germany really is over 3 day or 4 days, but Sunday-Tues are almost nothing because of less reporting on the weekends. So you see the trend over 3 days about the same spike 3-4 days then low 3 days, repeat sometimes the spikes grow a little each week, so you can measure the curve. Also the if you change 7 day to 14 days the incidence level is twice as high but at 3 days it is two times lower, and this is more consistent to what is really going on. Then take into consideration percent of population that has cases it very low, thankfully. In my city over 138,000 we have only 3% of the city who had it, and this does not grow fast. Add to this that quick testing (not so reliable) adds to the number of cases, but Germany stopped measuring reproduction ratio R and Growth rate is important.

So using your data above,
how would I calculate R(reproduction ratio) ? In simple terms, (I use Excel)
and how to calculate your growth rate formula above ?

Thanks