About this tool
What Is the LTV:CAC Ratio?
The LTV:CAC ratio compares the total gross profit a customer generates over their lifetime (LTV) against the cost to acquire that customer (CAC). It is the most important unit economics metric for subscription businesses.
A ratio of 3:1 or higher is considered healthy — the customer generates three dollars of profit for every dollar spent acquiring them. A ratio below 1:1 means you lose money on every customer you acquire.
How CAC Is Calculated
Customer Acquisition Cost (CAC) is the total cost of acquiring a single new customer:
CAC = Total Sales & Marketing Cost ÷ New Customers Acquired
Critically, "total cost" must include all acquisition-related expenses — not just ad spend. This includes:
- Paid advertising (Google, LinkedIn, Facebook)
- Sales team salaries and commissions
- Marketing software (HubSpot, Salesforce, etc.)
- Content creation and agency fees
- Event and conference costs
Omitting sales salaries is the most common mistake — it artificially lowers CAC and inflates the LTV:CAC ratio.
How LTV Is Calculated
Customer Lifetime Value (LTV) projects the total gross profit from a single customer before they churn:
LTV = Average MRR × Gross Margin × (1 ÷ Monthly Churn Rate)
The term (1 ÷ Monthly Churn Rate) estimates the average customer lifetime in months. At 5% monthly churn, the average customer stays 20 months. At 2% churn, they stay 50 months.
This formula shows why churn reduction has an outsized impact on business value — cutting churn from 5% to 2.5% doubles the LTV.
LTV:CAC Ratio Benchmarks
| LTV:CAC Ratio | Assessment | Implication |
|---|---|---|
| < 1:1 | Unprofitable | You lose money on every customer. Cut spend or fix churn. |
| 1:1 to 2:1 | Marginal | Barely breaking even. Unsustainable at scale. |
| 3:1 | Healthy | Industry benchmark. Sustainable growth. |
| 5:1+ | Strong | But may indicate under-investment in marketing. |
| 8:1+ | Under-investing | You could grow faster by spending more on acquisition. |
A very high LTV:CAC ratio (8:1+) actually signals a problem — you are leaving growth on the table by not investing enough in customer acquisition. Competitors with a 3:1 ratio who spend more will outgrow you.
CAC Payback Period
The payback period measures how many months it takes to recover the CAC from a customer's monthly gross profit:
Payback Period = CAC ÷ (MRR × Gross Margin)
Benchmarks:
- Under 12 months: Excellent. The customer becomes profitable within the first year.
- 12-18 months: Acceptable for enterprise SaaS with larger deal sizes.
- Over 24 months: Concerning. High risk if churn is also elevated.
A short payback period means faster cash flow recovery, which reduces the working capital needed to fund growth.
Practical Usage Examples
Healthy Enterprise SaaS
$50,000 spend, 10 customers, $1,000 MRR, 90% margin, 2% churn.
CAC: $5,000. LTV: $45,000. Ratio: 9.0x ✅. Payback: 5.6 months.High-Churn SMB SaaS
$20,000 spend, 100 customers, $50 MRR, 80% margin, 10% churn.
CAC: $200. LTV: $400. Ratio: 2.0x ⚠️. Payback: 5.0 months.Step-by-Step Instructions
Step 1: Enter Total Sales & Marketing Spend. Include all customer acquisition costs for a specific period: advertising, agency fees, sales team salaries, commissions, software subscriptions (CRM, marketing automation), and event costs.
Step 2: Enter New Customers Acquired. Count only net new paying customers gained during the same period as the spend above. Do not include renewals or upgrades.
Step 3: Enter Average Monthly Revenue. This is your ARPU (Average Revenue Per User) — the average monthly recurring revenue (MRR) generated by a single customer.
Step 4: Enter Gross Margin. Your gross profit margin percentage after deducting direct costs (hosting, support, payment processing). Typical SaaS gross margins are 70-90%.
Step 5: Enter Monthly Churn Rate. The percentage of customers who cancel each month. A 5% monthly churn means you lose 5 out of every 100 customers each month.
Core Benefits
Complete Unit Economics: Calculates all four critical SaaS metrics in one tool: CAC, LTV, LTV:CAC ratio, and payback period.
Investor-Ready Output: The LTV:CAC ratio is the primary metric venture capitalists use to evaluate SaaS businesses. This calculator produces the same metric VCs calculate during due diligence.
Churn-Aware LTV: Uses the formula LTV = MRR × Gross Margin × (1 / Monthly Churn Rate), which accurately reflects how churn limits the revenue a customer generates over their lifetime.
Instant Payback Period: Shows exactly how many months it takes to recover the CAC from a single customer's gross profit, helping you plan cash flow and marketing budgets.
No Email Gate: Results are displayed instantly without requiring your email, company name, or any contact information.
Frequently Asked Questions
A ratio of 3:1 is the industry benchmark — the customer generates three times the profit of the acquisition cost. Below 1:1 means you lose money on every customer. Above 5:1 may indicate you could grow faster by investing more in acquisition.
Divide your total sales and marketing spend by the number of new paying customers acquired in the same period. Include all costs: ad spend, sales salaries, commissions, software, agency fees, and events. CAC = Total Cost ÷ New Customers.
LTV = Average Monthly Revenue × Gross Margin × (1 ÷ Monthly Churn Rate). The churn rate determines customer lifetime — at 5% monthly churn, the average customer lasts 20 months. LTV represents total gross profit from that customer before they cancel.
Include everything spent to acquire customers: paid advertising, content marketing costs, sales team salaries and commissions, CRM and marketing automation software, agency retainers, conference booths, and any other direct acquisition expense. Omitting sales salaries is the most common mistake.
Because LTV uses the formula 1/Churn to estimate customer lifetime. At 2% churn, customers stay 50 months. At 10% churn, they stay only 10 months. Cutting churn in half doubles the LTV, which doubles the LTV:CAC ratio — making it the highest-leverage improvement for SaaS businesses.
Under 12 months is excellent for most SaaS businesses. Enterprise SaaS with higher deal values may accept 12-18 months. Over 24 months is concerning, especially if churn is also high, because customers may cancel before you recover the acquisition cost.
Yes. A very high ratio (8:1 or above) usually means you are under-investing in marketing. You are extracting high value from customers but not spending enough to acquire new ones. Competitors investing more aggressively will capture market share faster.
Include your LTV:CAC ratio and payback period on the unit economics slide. VCs expect to see a ratio of 3:1+ and a payback period under 18 months. Show the underlying assumptions (MRR, churn rate, gross margin) alongside the calculated metrics for credibility.
This calculator uses monthly churn rate. If you only know your annual churn rate, divide it by 12 for an approximate monthly figure. For example, 30% annual churn is approximately 2.5% monthly churn. Note: this approximation is not exact due to compounding, but is sufficient for initial calculations.
This calculator uses a simplified LTV model based on initial MRR and churn. It does not factor in upsells, cross-sells, or seat expansion. For businesses with significant net revenue retention above 100%, the actual LTV will be higher than the calculated figure.