Customer Retention Rate (CRR

Growth Strategy: Why You Must Subtract New Customers (E - N)

A common calculation error is simply dividing End Customers by Start Customers). If you start with 100 users, lose 50, and acquire 50 new ones, \ hides the fact that you lost half your customers!

The Standard CRR Formula

By using (E - N) / (S) × 100, you isolate the true retention behavior of your existing cohort without distortion from new sales marketing campaigns.

How to Use This Calculator

Enter your Number of Customers at Start of Period (S) (e.g. 1000), Total Number of Customers at End of Period (E) (e.g. 1050), New Customers Acquired During Period (N) (e.g. 150), Measurement Period Horizon — choose from Monthly Period (1 Month), Quarterly Period (3 Months), Annual Period (1 Year / 12 Months), and Average Revenue per Customer ( / period) [Optional] (e.g. 95.0). Results update instantly as you type — adjust any value to compare scenarios.

The Formula

Customer Retention Rate (CRR) & cohort churn formulas: Retention Rate (CRR \%) = [(E - N) / (S)] × 100\%: S = Customers at Start, E = Customers at End, N = New Customers Acquired Churn Rate (\%) = 100\% - CRR (\%) = [(S - (E - N)) / (S)] × 100\% Existing Customers = E - N Average Customer Lifespan = (1) / (Churn Rate (Fraction))

Worked Example

For example, a business starting the month with 1,000 customers (S), ending with 1,050 customers (E), and acquiring 150 new customers (N): Retained existing customers equal . The Customer Retention Rate is . The Churn Rate is \ (100 customers lost), yielding an average customer lifespan of 10.0 months.

Understanding Your Result

Benchmark monthly churn rates for SaaS: Best-in-class below 0.5%, good 0.5–1%, average 1–2%, above 2% requires urgent attention. Annual churn above 24% (2% monthly) means the business replaces its entire customer base every 4–5 years — growth becomes a treadmill. Net Revenue Retention (NRR) above 100% means existing customers expand faster than they churn — the most powerful growth lever available. Top-quartile SaaS companies have NRR above 120%. Monthly churn of 1% compounding annually equals 11.4% annual customer loss.