When to use this calculator
Retention focuses on how much of the original customer base remains after the period’s acquisitions are removed.
Explore the marketing & customer calculators for other questions in this topic. For a related calculation, use the Customer Satisfaction Score Calculator: Express satisfied survey responses as a percentage of valid responses.
PUTTING IT INTO PRACTICE
Customer Retention Rate: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Customers at period end (integer) | 450 |
| New customers during period (integer) | 70 |
| Customers at period start (integer) | 400 |
| Result | 95 % |
- Check the input labels and enter the example values above.
- Apply the relationship: Retention (%) = (ending customers − new customers)/starting customers × 100.
- The result is 95 %, rounded for display.
How to interpret your result
Assumes counts use consistent customer definitions and new customers are included in ending customers.
Define the event, audience and attribution window before calculating a rate. Clicks, customers and orders are different units. Acquisition cost and campaign CPA may cover different spending categories.
Frequently asked questions
Should I count unique users or total events?
Use the definition matching your metric. State it consistently because repeat events can produce a different rate from unique people.
When is the customer retention rate calculator useful?
Retention focuses on how much of the original customer base remains after the period’s acquisitions are removed.
How do I use the customer retention rate calculator?
Enter customers at period end (integer), new customers during period (integer), customers at period start (integer). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Retention (%) = (ending customers − new customers)/starting customers × 100.
What should I check before using the result?
Assumes counts use consistent customer definitions and new customers are included in ending customers.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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