Customer Retention Rate & Churn Economics Lab

Scenario presets

Customer Cohort & Unit Economic Inputs

Customers at start of period (S)

Customers at end of period (E)

New customers acquired (N)

Average revenue per user (ARPU) ($/period)

Gross margin percentage (%)

Period tracking interval

Retention & Lifetime Value Metrics

Calculating retention...

CRR

Customer Retention Rate (CRR): -
Customer Churn Rate: -
Customers churned / lost: -
Net customer cohort growth: -
Average customer lifetime: -
Customer Lifetime Value (LTV): -
LTV gain from +5% retention: -

12-Period Customer Cohort Survival & Revenue Decay Schedule

Simulation of an initial 1,000-customer cohort over 12 periods under the calculated retention rate.

Cohort retention schedule showing period number, active customers, churned customers, cumulative churn, and cohort revenue.
Period	Active Surviving Customers	Customers Churned	Retention Survival (%)	Cohort Revenue ($)	Cohort Gross Profit ($)

Sensitivity Analysis 1: Starting Customers vs. Churned Customers on Retention Rate (CRR %)

Retention sensitivity across customer base scale and period churn volumes.

Customer retention rate by starting customers and lost customers. Rows change starting customers, columns change lost customers.
Starting Customers \ Churned	50 Lost	75 Lost	100 Lost (Base)	125 Lost	150 Lost

Sensitivity Analysis 2: Retention Rate (%) vs. ARPU ($) on Customer Lifetime Value (LTV $)

Unit economic compounding: how improving customer retention expands LTV across pricing tiers.

Customer lifetime value by retention rate and ARPU. Rows change retention rate, columns change ARPU.
Retention Rate % \ ARPU	$50	$75	$100 (Base)	$150	$200

Formulas and worked example

Customer Retention Rate (CRR) = $[(E - N) / S] \times 100\%$
Customer Churn Rate = $100\% - \text{CRR} = (L / S) \times 100\%$
Customers Lost ($L$) = $S + N - E$
Average Customer Lifetime = $1 / \text{Churn Rate Decimal} = 1 / (1 - \text{CRR Decimal})$
Customer Lifetime Value (LTV) = $\text{ARPU} \times \text{Gross Margin Decimal} \times \text{Customer Lifetime}$
Net Customer Growth Rate = $[(E - S) / S] \times 100\%$

A SaaS provider starts the month with 1,000 customers ($S$). Over the month, it signs up 150 new customers ($N$) and closes with 1,050 total subscribers ($E$). Customers lost equal $1,000 + 150 - 1,050 = 100$. The Customer Retention Rate is $[(1,050 - 150) / 1,000] \times 100\% = 90.00\%$, indicating a 10.00% monthly churn rate. The implied average customer lifetime is $1 / 0.10 = 10.0$ months. At a $100/mo ARPU and 75% gross margin, baseline Customer Lifetime Value is $\$100 \times 0.75 \times 10.0 = \$750.00$. If retention improves by 5% to 95% (cutting churn in half to 5%), customer lifetime doubles to 20 months, skyrocketing LTV to $1,500.00 (a 100% value expansion).

Self-check quiz

1. Why must new customers acquired ($N$) be subtracted from ending customers ($E$) when calculating Customer Retention Rate?

To isolate genuine repeat retention of existing customers from new acquisition momentum

New customers are legally prohibited from retention metrics

2. If a company begins a quarter with 500 customers, acquires 80 new ones, and finishes with 540 customers, how many customers churned?

40 customers (500 + 80 - 540)

80 customers

3. A subscription platform with a 96% monthly retention rate (4% monthly churn) has an implied average customer lifetime of:

25 months (1 / 0.04)

12 months

4. According to landmark Bain & Company research, increasing customer retention by 5% can increase company profits by:

25% to 95%, because retained customers buy more and incur zero acquisition costs

Exactly 5%

Frequently asked questions

What is Customer Retention Rate (CRR) and how is it calculated?

Customer Retention Rate (CRR) measures the percentage of existing customers a business retains over a specific period. The standard formula is: CRR = ((End Customers - New Customers Acquired) / Start Customers) * 100%. Subtracting new customer acquisitions isolates true repeat retention from new customer acquisition momentum.

How does Customer Retention Rate relate to Customer Churn Rate?

Customer Retention Rate and Churn Rate are direct mathematical complements: Retention Rate + Churn Rate = 100%. If a business has an 85% monthly retention rate, its customer churn rate is exactly 15%.

How does a small increase in customer retention drive disproportionate profit growth?

Research by Bain & Company and Harvard Business School shows that increasing customer retention by just 5% can expand bottom-line profits by 25% to 95%. Retained customers spend more over time, incur zero marginal acquisition costs (CAC), generate word-of-mouth referrals, and dramatically elevate Customer Lifetime Value (LTV).

How do you calculate average customer lifetime from the retention rate?

Average customer lifetime equals 1 divided by the period churn rate: Lifetime = 1 / (1 - Retention Rate). For example, a subscription service with a 5% monthly churn rate (95% retention) retains average subscribers for 20 months (1 / 0.05).