I’m trying to calculate retention on a quicksight table but I’m unable to calculate the percentage difference against a fixed value. This is the view of my current pivot table. I want to calculate the retention percentage so that would be customers retained / original number of customers where customers retained is the count at each month after launch and original number of customers is the count at month 0. I want to do this based on cohort date. So for example on my current table for the cohort on Jul 1, 2018, column 0 would have 100%, column 1 would have, 100%, and column 2 would have 50%.

If I use that, would I have to manually change the offset per column? I would want them all to compare to column 0, but I don’t know how many columns I would have (could be anywhere from 3 to 32 columns). Would there be a way to always compare to the same column?