Project list size forward given sign-up rate, unsubscribes and bounce attrition.
A list is a leaky bucket: attrition scales with size while additions usually do not, so growth slows and eventually stops at the point where additions equal attrition. The closed form of that geometric series gives the projection directly. Every list has an equilibrium size set by additions divided by attrition rate, and no amount of time gets it past that ceiling without raising sign-ups or cutting churn.
Email List Growth
List next month = list × (1 − attrition rate) + new subscribers
List next month = list × (1 − attrition rate) + new subscribers A list is a leaky bucket: attrition scales with size while additions usually do not, so growth slows and eventually stops at the point where additions equal attrition. The closed form of that geometric series gives the projection directly.
Every list has an equilibrium size set by additions divided by attrition rate, and no amount of time gets it past that ceiling without raising sign-ups or cutting churn.
This calculator takes 5 inputs: Current list size, New subscribers per month, Monthly unsubscribe rate, Monthly bounce and cleaning attrition, Months to project. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.