Net Dollar Retention tracks the revenue generated by a cohort (a set of customers grouped by sign-up period) over time, compared to the sign-up date of the cohort. Net Dollar Retention shows the net impact that expansion, contraction, and churn have on revenue.
Where a cohort is the set of new customers in month n, and x = the number of months since month n:
Example: n = Jan 2021, x = 3
SaaSGrid also computes the weighted average (Average) across cohorts.
For quarterly and annual aggregation, the formula is applied using revenue from the last month of the period.