The Newsletter Growth Calculator estimates how a subscriber list changes when acquisition and churn repeat each month. Publishers can use it to compare campaign targets, referral programs, and expected unsubscribe pressure. The model displays both ending subscribers and net growth, making it easier to see whether acquisition is merely replacing churn or building the list.
Use the active subscriber count at the start of the projection.
Enter the average number of new subscribers expected each month.
Use the share of the list expected to unsubscribe or become inactive each month.
Review the ending list and the accumulated gains and losses.
Churn is applied to the opening subscriber balance for each month, then new subscribers are added.
The ending count reflects compounding churn rather than a one-time subtraction.
Real campaigns often have seasonal acquisition and churn, so use an average or run separate phases.
Given: 5,000 starting subscribers, 600 new subscribers per month, 2% monthly churn, and 12 months.
Calculation: Each month, multiply the current list by 0.98 and then add 600.
Result: The final count shows how repeated acquisition compounds against ongoing churn.
New subscribers are added after that month’s churn in this model, so they begin facing churn in the following month.
Convert both acquisition and churn to weekly assumptions and interpret the period as weeks only if you also adapt the period unit consistently.
Run separate scenarios or use a weighted monthly average.
Only if the starting list, additions, and churn all use your definition of active or engaged subscriber.
Adjust monthly additions until the projected ending list reaches your target.