SaaS LTV, CAC & Payback Period Calculator
Evaluate customer lifetime value, audit your LTV:CAC ratio health against venture benchmarks, and measure cash payback velocity in months.
Customer Lifetime Value (LTV) and Customer Acquisition Cost (CAC) determine the fundamental unit economics of subscription businesses. Margin-Adjusted Net LTV is defined as Net LTV = (Monthly ARPU × Gross Margin %) / Monthly Churn Rate. The LTV:CAC Ratio measures capital return efficiency: LTV:CAC = Net LTV / Fully-Loaded CAC, where a 3.0x to 5.0x ratio represents the optimal venture scaling benchmark.
Equally critical is the CAC Payback Period, which quantifies the exact number of months required for a customer’s gross profit contribution to fully recover acquisition expenses: Payback Months = CAC / (Monthly ARPU × Gross Margin %). High-performing SaaS organizations maintain payback periods under 12 months, while payback timelines beyond 18 months place severe strain on working capital and working cash runways.
1. Subscription Unit Metrics
Instant client-side model2. Diagnostic Health Output
Sub-Optimal (Cash Flow Strain)Now that you know your LTV, find the maximum Google & LinkedIn Ads click bid (CPC) you can afford to pay without breaking your 3:1 unit economics.
Launch SaaS Reverse Funnel Simulator →SaaS LTV:CAC & Payback Benchmarks by Growth Stage
How venture capital investors evaluate subscription unit efficiency:
| Company Stage | Target LTV:CAC | Target Payback (Mo) | Max Monthly Churn | Growth Strategic Focus |
|---|---|---|---|---|
| Early Stage / Seed | > 2.5x | < 9 Months | 3.0% – 5.0% | Validating Product-Market Fit and organic retention |
| Series A / Scaling | 3.0x – 4.5x | 10 – 14 Months | 1.5% – 3.0% | Optimizing paid acquisition channels & SDR outbound funnels |
| Growth / Series B+ | 4.0x – 6.0x | 12 – 18 Months | < 1.5% | Multi-product expansion, Net Revenue Retention (NRR > 115%) |
| Enterprise SaaS | 5.0x+ | 15 – 24 Months | < 0.8% | Long contract lock-ins, high expansion, and low logo churn |
Frequently Asked Questions
What is the formula for SaaS Net LTV?
(Monthly ARPU * Gross Margin %) / Monthly Churn %. By factoring in gross margin, this equation reflects the true gross cash contribution generated over a customer's lifetime rather than superficial top-line billing.