Why growth slows down even when nothing goes wrong
Two sliders draw your real 24-month curve, plateau and all.
Growth Curve Simulator calculator
Your numbers
Your result
Active customers, month by month
Reading the curve
This is the single most common reason clients lose confidence in a campaign around month six. Growth flattening is arithmetic, not failure — and showing it in advance protects the relationship.
The recurrence
Each month: customers × (1 − churn) + new arrivals. Growth is fast while the base is small, because few people are leaving.
Why it flattens
As the base grows, the number leaving grows with it. Eventually departures equal arrivals and the curve goes flat.
Months to 80%
log(0.2) ÷ log(1 − churn). Higher churn reaches its (lower) ceiling faster — which is why bad businesses plateau early.
The trade-off
Halving churn doubles the ceiling but roughly doubles the time to reach it. More upside, more patience required.
What to expect
If your curve flattens at month 8, that is your model, not your marketing. Raising spend alone will not change the shape.
How to move it
Only two levers change the ceiling: keep people longer, or charge more. Volume changes how fast you get there, not where you stop.