Customer Retention RatevsLifetime Value (LTV)

Customer Retention Rate measures the percentage of customers who remain with your business over a given period. A 90% annual retention rate means you lose 10% of your customers each year. For subscription businesses, improving retention from 90% to 95% can double your customer lifetime value because the average customer stays twice as long.

Lifetime Value is the total revenue you can expect from a single customer over the entire duration of your relationship. It is the most critical number for understanding how much you can afford to spend on acquiring customers. The simplest formula: LTV = ARPU ÷ Monthly Churn Rate. A customer paying $100/month with 5% monthly churn has an LTV of $2,000. Netflix's LTV exceeds $1,200 per subscriber because churn is below 2.5% — this justifies their $17B+ annual content spend. LTV is the roof of your building: it determines the maximum CAC you can afford, the features you can build, and the team you can hire.

Don't confuse customer retention rate with revenue retention — they measure different things. You can retain 95% of customers but lose 30% of revenue if your biggest accounts are the ones leaving. Also, looking at retention quarterly instead of monthly hides problems — a 95% quarterly retention rate is actually 83% annual retention.

Most founders massively overestimate LTV by assuming customers will stay forever. In reality, early-stage startups have limited cohort data. A startup with 6 months of history claiming $3,000 LTV is extrapolating a trend that hasn't been validated. Use conservative estimates (12-24 months cap) until you have 3+ cohorts with 12+ months of data. Also, LTV should be calculated on gross margin, not revenue — a $2,000 LTV with 50% gross margin means only $1,000 in actual profit to cover acquisition costs.

Calculate retention rate monthly: (Customers at End of Period − New Customers) ÷ Customers at Start × 100. Segment by cohort and plan: aim for 95%+ monthly customer retention for B2B SaaS and 85%+ for B2C. Set up automated alerts when retention dips below your target for two consecutive months.

Calculate LTV two ways: (1) Simple: ARPU ÷ Monthly Churn Rate. (2) Cohort-based: track actual revenue from each monthly cohort over time. Compare them — if your cohort LTV is lower than your formula LTV, your churn rate is misleading you (possibly due to early-life churn spikes). Always report Gross Margin-adjusted LTV: LTV × Gross Margin. This is the number that matters for unit economics.