How to use this calculator
- Enter or choose customers at the start (S).
- Enter or choose customers at the end (E).
- Enter or choose new customers during the period (N).
- The customer retention rate updates as you type. Use Copy result or Share to keep it.
Method
Retention rate = (E − N) ÷ S × 100; Churn = 100 − Retention
- S
- customers at the start of the period
- E
- customers at the end
- N
- new customers acquired during the period
Worked example
- Retained = 1,100 − 250 = 850.
- Retention = 850 ÷ 1,000 = 85%.
- Churn = 100 − 85 = 15%, or 150 customers lost.
The business kept 85% of its starting customers and lost 15%, even though the total grew by 10%.
What the result means
Compare retention only over equal periods and with the same definition of an active customer. For non-subscription shops, define “customer” as someone who bought within a set window, such as the last 12 months.
Assumptions and limits
- New customers acquired during the period are not counted as retained.
- It is a single-period figure; cohort analysis shows how retention changes with customer age.
Questions
Why subtract new customers?
Otherwise acquisition can mask losses. Subtracting them leaves only the customers you started with.
What counts as a customer in a non-subscription shop?
Choose a rule, such as purchased in the last 12 months, and apply it to both the start and end counts.