Customer Retention Rate Calculator
Calculate your customer retention rate (CRR) over any period by comparing the number of customers at the start and end of the period, accounting for new customers acquired.
How to use this tool
- Enter customers at start of period, customers at end of period and new customers acquired during period in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your customer retention rate and the full breakdown beneath it.
⚠ This tool provides general estimates for education only and is not financial, tax or legal advice. Figures may not reflect your situation — verify with a qualified professional.
Formula
Customer Retention Rate:
CRR = ((E − N) / S) × 100
Customer Churn Rate: Churn = 100% − CRR
Where E = customers at end of period, N = new customers acquired, S = customers at start of period.
How it works
Customer retention rate measures the percentage of existing customers a business retains over a defined time period. By subtracting new customers acquired (N) from the ending total (E), we isolate the number of original customers who stayed, then divide by the starting base (S).
This formula is the industry-standard method popularized by HubSpot and other CRM platforms. It assumes that all customers at the end of the period are either carried over from the start or newly acquired — customers who left and returned in the same period are not separately tracked in this simplified model.
Worked example
Calculating monthly customer retention rate
- Start of month: 1,000 customers (S = 1,000)
- End of month: 950 customers (E = 950); new customers acquired: 100 (N = 100)
- Customers retained from original base = E − N = 950 − 100 = 850
- CRR = (850 / 1,000) × 100 = 85%
- Churn Rate = 100% − 85% = 15%; customers lost = 1,000 − 850 = 150
Customer retention rate is 85%, meaning 850 of the original 1,000 customers remained. 150 customers were lost during the period.
Common mistakes to avoid
- Subtracting new customers after the retention calculation rather than before, which inflates apparent retention by counting newly acquired customers as retained.
- Using total end-of-period customer count without deducting new customers acquired during the period -- the most common formula error that produces CRR above 100% in growth phases.
- Comparing CRR across periods of different lengths -- a 90% monthly retention rate is very different from a 90% annual retention rate.
Key terms
- Customer Retention Rate (CRR)
- The percentage of customers a company retains from the beginning to the end of a measurement period, excluding new customers acquired.
- Customer Churn Rate
- The percentage of customers lost during a period, calculated as 100% minus the retention rate.
- Customer Lifetime Value (CLV)
- The total revenue a business can expect from a single customer over the entire duration of their relationship; directly improved by higher retention rates.
- Net Revenue Retention (NRR)
- A related metric that measures retained revenue (including upsells and expansions) rather than just the count of retained customers.
Frequently asked questions
- What is a good customer retention rate?
- SaaS companies often target 85-95% annual retention. E-commerce may see 25-40% annual repeat purchase rates. Subscription services typically aim for monthly churn below 2-3%.
- How does retention rate connect to customer lifetime value?
- Average customer lifespan = 1 / Churn Rate. At 2% monthly churn, average lifespan is 50 months. Multiply by average monthly revenue per customer to get LTV. Higher retention directly increases LTV.
- How is retention rate different from renewal rate?
- Retention rate measures the percentage of customers who remain active over a period. Renewal rate specifically measures customers who actively renew at the end of a fixed contract term. Both matter but measure different things.