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
Educational Purpose Disclaimer
This calculator is provided for informational and educational estimation purposes only. All calculations and projections are based on standard mathematical formulas and assumed inputs. The output values should not be considered professional financial, legal, tax, or medical advice. ProCalc is not a registered financial advisor or licensed practitioner. Always consult a qualified professional (such as a Chartered Accountant, certified planner, or physician) before making major decisions.
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
Frequently Asked Questions
**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:** $$\text{CAC Payback (Months)} = \frac{\text{CAC}}{\text{Monthly Gross Profit}}$$ $$\text{LTV : CAC Ratio} = \frac{\text{LTV}}{\text{CAC}}$$
Disclaimer: This tool is provided for informational and calculation purposes. Output values are estimates based on standard user inputs.