Customer Retention Rate Calculator

About this calculator

Customer retention rate measures the share of a company’s existing customer base that stays through a given period, calculated as (customers at period end − new customers acquired during the period) ÷ customers at the start of the period, expressed as a percentage. Subtracting new customers matters because without it, strong new-customer growth could mask serious churn among the customers a business already had.

Retention rate is the mirror image of churn rate (100% minus retention roughly equals churn), and because acquiring a new customer typically costs far more than keeping an existing one, even small improvements in retention tend to have an outsized effect on long-term revenue and customer lifetime value. Subscription businesses, SaaS companies and customer-success teams track this metric monthly or annually as a core health indicator alongside churn and lifetime value.