Definition: The percentage of users who return to your product or service after a specific period (e.g., day 1 retention, week 4 retention, monthly retention).

How to Calculate:

• Specific Period Retention: $ \text{Retention Rate (Day X)} = (\text{Number of Users Active on Day X} / \text{Number of Users Acquired on Day 0}) \times 100%$
• For general retention over a period: $ \text{Retention Rate} = ((\text{Customers at End of Period} – \text{New Customers Acquired During Period}) / \text{Customers at Beginning of Period}) \times 100%$