Customer Retention Rate
GeneralCustomer Retention Rate
The percentage of existing customers a business keeps over a given period, excluding new customers acquired during that same period.
Definition
Customer Retention Rate (CRR) measures the percentage of existing customers a business successfully keeps over a defined period, deliberately excluding any new customers acquired during that same window. It answers the question: "Of the customers we had at the start of this period, what percentage are still with us at the end?"
Retention rate is one of the most important health metrics for subscription and recurring-revenue businesses, because it isolates the durability of the existing customer relationship from the effects of new customer acquisition — a company can grow its total customer count while still having a serious retention problem underneath.
Formula
Customer Retention Rate = ((E − N) / S) × 100
Where:
- E = Number of customers at the end of the period
- N = Number of new customers acquired during the period
- S = Number of customers at the start of the period
The (E − N) term isolates the count of existing customers who remained, removing new sign-ups from the numerator so the metric purely reflects retention of the original base.
Worked Example
A subscription box company tracks its customer base over one quarter:
| Metric | Value |
|---|---|
| Customers at start of quarter (S) | 1,000 |
| Customers at end of quarter (E) | 1,150 |
| New customers acquired during quarter (N) | 250 |
Customer Retention Rate = ((1,150 − 250) / 1,000) × 100 = 90%
Despite the total customer count growing by 150, the retention rate of 90% means 10% of the original 1,000 customers were lost during the quarter. Use the Customer Retention Rate calculator to compute this for your own start, end, and new-customer figures.
Key Things to Know
- Retention rate and Churn Rate are two sides of the same coin: Retention Rate = 100% − Churn Rate over the same period, so improving one automatically improves the other — track whichever framing your team finds more actionable.
- New customer acquisition can mask a retention problem: A rising total customer count driven entirely by new sign-ups can hide declining retention among existing customers — always look at retention rate independently of top-line growth.
- Cohort-based retention reveals more than a single blended number: Tracking retention rate by acquisition month or channel (cohort analysis) shows whether retention is improving or worsening for newer customers specifically, rather than averaging over the whole base.
- Small retention gains compound into large CLV gains: Because retained customers keep generating revenue, even a few percentage points of retention improvement can substantially increase lifetime value and reduce the payback pressure on CAC.
- Retention rate should be measured consistently: Use the same period length (monthly, quarterly, annual) and the same definition of "active customer" every time you calculate it, so trends over time are genuinely comparable.
Frequently Asked Questions