CAC Payback & Customer LTV Ratio Engine
Calculate CAC Payback Period (months), LTV:CAC Ratio, customer lifetime, and unit economics health.
CAC Payback & Customer LTV Ratio Engine
Calculate CAC Payback Period (months), LTV:CAC Ratio, customer lifetime, and SaaS unit economics health.
⚙️ Acquisition & Customer Metrics
🎯 SaaS Benchmark Evaluation
What is the CAC Payback & Customer LTV Ratio Engine?
The CAC Payback & Customer LTV Ratio Engine helps B2B SaaS founders, DTC e-commerce brands, and agency owners evaluate customer acquisition efficiency and SaaS unit economics.
Two primary metrics govern startup profitability and venture capital readiness:
1. CAC Payback Period (Months): The number of months required for a new customer's gross profit to fully recover the cost spent acquiring them (CAC).
- *Benchmark*: Under 12 months for B2B SaaS is world-class.
2. LTV : CAC Ratio: The ratio of total gross margin lifetime value (LTV) generated by a customer compared to their acquisition cost.
- *Benchmark*: 3.0x or higher indicates a healthy, scalable business.
This calculator computes CAC Payback Period, Customer Lifetime (Months), Lifetime Value (LTV), LTV:CAC Ratio, and Unit Economics Grade.
How Does the CAC Payback & Customer LTV Ratio Engine Work?
1. Enter Customer Acquisition Cost (CAC) — Blended ad spend + sales costs per acquired user ($ or ₹).
2. Set Monthly ARPU & Gross Margin % — Average revenue per user per month and gross profit margin.
3. Input Monthly Churn Rate (%) — Percentage of customers cancelling subscription each month.
4. View Unit Economics Dashboard — Instantly review CAC Payback months, LTV, LTV:CAC ratio, and health grade.
Formula & Calculation Method
1. Customer Lifetime (Months):
$$\text{Lifetime (Months)} = \frac{1}{\text{Monthly Churn %} / 100}$$
2. Gross Margin Lifetime Value (LTV):
$$\text{Monthly Gross Profit} = \text{ARPU} \times \left( \frac{\text{Gross Margin %}}{100} \right)$$
$$\text{LTV} = \text{Monthly Gross Profit} \times \text{Lifetime (Months)}$$
3. CAC Payback Period (Months) & LTV:CAC Ratio:
$$\text{CAC Payback (Months)} = \frac{\text{CAC}}{\text{Monthly Gross Profit}}$$
$$\text{LTV : CAC Ratio} = \frac{\text{LTV}}{\text{CAC}}$$
Example Calculation
Example: SaaS Startup with $300 CAC, $50/mo ARPU, 80% Gross Margin, 2.5% Monthly Churn
- Monthly Gross Profit per User: $50 × 0.80 = $40 / month
- Customer Lifetime: 1 ÷ 0.025 = 40 Months (3.3 Years)
- Lifetime Value (LTV): $40 × 40 = $1,600
Unit Economics Results:
- CAC Payback Period: $300 ÷ $40 = 7.5 Months (Excellent! <12 mos)
- LTV : CAC Ratio: $1,600 ÷ $300 = 5.33x (Highly profitable unit economics)
- Grade: ⭐ A+ World Class