Acquiring customers.
Keeping the value.
Customer growth can hide revenue leakage. Separate customer churn, lost recurring revenue and expansion before deciding whether acquisition spend is solving the right problem.
Monthly subscription model · ZAR · illustrative starting values. Calculations run in your browser; calculator inputs are not saved or uploaded. Optional website analytics records interactions, not the amounts entered. Use paying customers and their recurring revenue from the same starting cohort.
One month. One starting cohort.
If the same churn rate persisted
Starting customer cohort remaining over 12 months. No new customers or reactivations.
What this changes in the decision
Count the cohort. Then explain the movement.
Customer churn
Lost starting-cohort customers ÷ starting customers. New customers are excluded. A customer added and lost within this month belongs to a separate cohort.
Revenue retention
Gross revenue churn = (churned MRR + contraction) ÷ starting MRR. GRR = 1 − gross revenue churn. NRR = (starting MRR − churned MRR − contraction + expansion) ÷ starting MRR. NRR can exceed 100%.
Revenue retention definitions ↗Cohort scenario
Remaining customers after n months = starting customers × (1 − monthly churn)n. This assumes a constant rate. It is a sensitivity illustration, not a forecast; real retention changes by tenure, customer segment and cohort.
Where I would go next
Break retention down by acquisition cohort, channel and product. Check cancellation reasons, onboarding, activation and customer quality. Link acquisition cost to realised customer value using deduplicated customer records. This calculator alone cannot establish CAC, LTV or the cause of churn.
MRR is recurring monthly run rate, not cash received or recognised accounting revenue. This model is intended for paid recurring relationships; a one-off purchase business needs a defined repeat-purchase window instead.