Why LTV Is the Most Important Metric You're Probably Miscalculating
Customer Lifetime Value (LTV or CLV) determines how much you can afford to pay to acquire each customer and remain profitable. Get this wrong and your entire growth strategy — especially paid acquisition — is built on a broken foundation.
The LTV Formula (and Why Most People Use the Wrong One)
The basic LTV formula: LTV = Average Revenue Per User × Gross Margin % × (1 ÷ Churn Rate)
Example: $120/month ARPU × 70% gross margin × (1 ÷ 8% monthly churn)
= $84 × 12.5 months = $1,050 LTV
The Customer Lifetime Value Calculator automates this calculation and also models the LTV:CAC ratio to help you determine if your growth economics are sustainable.
The Critical Mistake: Using Gross Revenue Instead of Gross Profit
LTV must be calculated on gross profit, not gross revenue. If you have $120/month in revenue but $40/month in infrastructure and support costs, your gross margin is 67%. Your LTV is not $120 × 12.5 = $1,500. It's $80 × 12.5 = $1,000. This difference makes or breaks your CAC limits.
The LTV:CAC Ratio — The Metric Investors Care Most About
The LTV:CAC ratio measures capital efficiency of growth. Industry benchmarks:
- LTV:CAC < 1:1: Every customer costs more than they're worth. Fatal.
- LTV:CAC 1:1 to 2:1: Breaking even on acquisition. Unsustainable at scale.
- LTV:CAC 3:1: The benchmark for healthy SaaS growth.
- LTV:CAC 5:1+: Excellent. May indicate underinvestment in acquisition.
Use the Customer Lifetime Value Calculator alongside the CAC Payback Calculator to determine your ratio and benchmark it against these ranges.
How to Increase LTV: The 4 Levers
- Reduce churn: The highest-leverage lever. Halving churn approximately doubles LTV.
- Increase ARPU via upsells: Moving customers from a $50/month plan to an $80/month plan increases LTV by 60% with no change to churn.
- Improve gross margin: Reducing infrastructure costs or support overhead directly increases LTV.
- Expand contract length: Annual plans reduce effective monthly churn to near zero for the contract period.