The LTV:CAC Ratio Calculator computes the relationship between Customer Lifetime Value (LTV) and Customer Acquisition Cost (CAC) — the foundational unit economics metric for any subscription or recurring-revenue business. The ratio answers the most important question in growth finance: does acquiring a customer create more value than it costs? A 3:1 ratio means every rupee spent on acquisition generates three rupees in customer lifetime value; a ratio below 1:1 means acquisition is actively destroying value.
LTV:CAC ratio is the lens through which every growth investment decision should be evaluated. It determines how aggressively a business can scale paid acquisition, what pricing changes are worth pursuing, and whether the current retention rate is high enough to support the growth model. For Indian SaaS companies raising Series A or B funding, demonstrating LTV:CAC above 3:1 is often a prerequisite — investors use it to assess whether the business model is fundamentally sound before evaluating growth rate.
This calculator also derives two additional outputs that add important context: CAC Payback Period (how many months until the customer pays back their acquisition cost through gross profit) and Net LTV (the actual value retained per customer after subtracting acquisition cost). Together, these three metrics give a complete picture of acquisition economics.
For context on the inputs to this calculator, the Customer Lifetime Value Calculator computes LTV from monthly revenue, gross margin, and churn rate. The Churn Rate Calculator computes the churn rate that feeds into LTV. The Customer Retention Rate Calculator shows the same dynamic from the retention angle. Used together, these four calculators give a complete view of the SaaS unit economics chain from acquisition through retention.
How to use this LTV:CAC calculator
Enter Customer Lifetime Value (LTV) — the total gross revenue expected from a customer over their entire relationship with the business. If you have not calculated this, use the CLV Calculator first, which derives LTV from monthly revenue, gross margin, and churn rate.
Enter Customer Acquisition Cost (CAC) — the average cost to acquire one new customer, including all sales and marketing spend allocated to acquisition. Divide total acquisition-related spend by new customers acquired in the same period.
Enter Monthly Revenue per Customer — the average monthly recurring revenue (MRR) per customer. Used to compute the monthly gross profit figure for the payback period calculation.
Enter Gross Margin (%) — the percentage of revenue remaining after direct costs. For pure SaaS, this is typically 60–85%. For businesses with significant fulfilment or onboarding costs, it may be lower.
Read your results — LTV:CAC Ratio with health badge, CAC Payback Period with colour coding, and Net LTV with directional colouring (green for positive, red for negative).
Formula & Methodology
LTV:CAC Ratio = LTV ÷ CACMonthly Gross Profit per Customer = Monthly Revenue × Gross Margin (%)CAC Payback Period (months) = CAC ÷ Monthly Gross ProfitNet LTV = LTV − CACWorked example using realistic values:
An Indian B2B SaaS company:
- LTV: ₹1,20,000 (from CLV calculator: ₹8,000/month × 70% margin ÷ 4.2% monthly churn)
- CAC: ₹30,000 (₹30 lakh marketing spend ÷ 100 new customers)
- Monthly Revenue per Customer: ₹8,000
- Gross Margin: 70%
LTV:CAC Ratio = 1,20,000 ÷ 30,000 = 4:1 — Healthy
Monthly Gross Profit = ₹8,000 × 70% = ₹5,600
CAC Payback Period = ₹30,000 ÷ ₹5,600 = 5.4 months — Excellent
Net LTV = ₹1,20,000 − ₹30,000 = ₹90,000Assumptions:
- LTV input should be gross LTV (before subtracting CAC), not net LTV. This calculator shows net LTV as a derived output.
- CAC should reflect blended acquisition cost across all channels (paid, organic, sales), not just advertising spend. Blended CAC gives the most accurate picture of total acquisition economics.
- Payback period uses gross margin, not contribution margin. If there are significant variable costs beyond direct product costs (implementation, onboarding, support), adjust gross margin downward to reflect true per-customer economics.
- This calculator uses a simplified LTV model assuming constant revenue per customer and constant churn rate. Businesses with strong negative churn (net revenue retention >100% from expansion) will have higher effective LTV than the simplified formula suggests.
Frequently Asked Questions
What is the LTV:CAC ratio?
The LTV:CAC ratio compares the total revenue a customer generates over their lifetime (Customer Lifetime Value) to the cost of acquiring that customer (Customer Acquisition Cost). An LTV:CAC ratio of 3:1 means the business earns ₹3 (or $3) in customer value for every ₹1 spent on acquisition. It is the fundamental unit economics test for any subscription or recurring-revenue business — a ratio below 1:1 means the business literally loses money on every customer acquired.
What is a good LTV:CAC ratio?
A ratio of 3:1 is the widely cited minimum benchmark for a healthy SaaS business — the '3× rule' used by most growth investors. Between 3:1 and 5:1 is considered healthy and scalable, as it leaves enough margin to fund growth and operations. Above 5:1 is excellent but can sometimes indicate underinvestment in acquisition — if the ratio is very high, it may mean the business could profitably spend more on marketing and grow faster. Below 1:1 is critical — the business is destroying value with every customer acquired.
What is the formula for LTV:CAC ratio?
LTV:CAC Ratio = Customer Lifetime Value (LTV) ÷ Customer Acquisition Cost (CAC). LTV is typically calculated as: Average Monthly Revenue per Customer × Gross Margin (%) ÷ Monthly Churn Rate. CAC is total sales and marketing spend in a period divided by new customers acquired in the same period. This calculator lets you input LTV and CAC directly, and also derives CAC Payback Period and Net LTV as additional decision-making outputs.
What is CAC payback period and why does it matter?
CAC payback period is the number of months it takes to recover the cost of acquiring a customer through gross profit from that customer. It is calculated as: CAC ÷ (Monthly Revenue per Customer × Gross Margin). A payback period under 12 months is considered excellent — the customer has paid back their acquisition cost within a year. Between 12–24 months is acceptable for most SaaS businesses with strong retention. Above 24 months is risky, as it requires the business to maintain sufficient working capital to bridge the acquisition investment before customers become profitable.
How is LTV calculated for the LTV:CAC ratio?
LTV (Customer Lifetime Value) = Average Monthly Revenue per Customer × Gross Margin (%) × Average Customer Lifespan (months). Average Customer Lifespan = 1 ÷ Monthly Churn Rate. For example: ₹5,000 monthly revenue, 75% gross margin, 3% monthly churn rate gives LTV = ₹5,000 × 0.75 ÷ 0.03 = ₹1,25,000. Use the [Customer Lifetime Value Calculator](/clv-calculator/) to compute LTV before entering it here, or the [Churn Rate Calculator](/churn-rate-calculator/) to compute the churn rate input for the CLV formula.
What is CAC and how is it calculated?
Customer Acquisition Cost (CAC) is the total cost of acquiring one new customer, including all sales and marketing spend, salaries, tools, and ad spend allocated to acquisition in a period. CAC = Total Sales & Marketing Spend ÷ New Customers Acquired. For example: if a company spent ₹10 lakh on marketing in a quarter and acquired 100 new customers, CAC = ₹10 lakh ÷ 100 = ₹10,000 per customer. Exclude existing-customer revenue (upsells) and retention spend from the CAC numerator — only count acquisition-focused costs.
What is net LTV and what does it tell you?
Net LTV (or gross profit from a customer after accounting for acquisition cost) = LTV − CAC. It represents the actual value generated per customer after subtracting what it cost to win them. Net LTV should be positive for a sustainable business. If LTV is $5,000 and CAC is $1,500, Net LTV is $3,500 — the business retains $3,500 in value per customer. This metric is useful for capacity planning and evaluating acquisition efficiency: a high LTV with high CAC may produce a lower Net LTV than a moderate LTV with very low CAC.
Why do investors focus so much on the LTV:CAC ratio?
The LTV:CAC ratio is the clearest signal of whether a business's growth is creating or destroying value. A high-growth company with an LTV:CAC below 1:1 is paying to lose money faster — growth accelerates destruction. A business with LTV:CAC above 3:1 has mathematically proven that its acquisition engine creates durable value with each customer added. Investors also use CAC payback period alongside LTV:CAC: a 5:1 ratio with a 36-month payback period means the business needs significant working capital to finance growth, which affects the funding requirement.
How does churn rate affect the LTV:CAC ratio?
Churn rate is the primary lever for LTV — reducing churn directly increases average customer lifespan, which multiplies LTV. A business with 5% monthly churn has a 20-month average customer lifespan; reducing churn to 2.5% doubles lifespan to 40 months and doubles LTV, which in turn doubles the LTV:CAC ratio with no change to CAC. This is why customer success investment is often more ROI-efficient than acquisition investment: one reduces churn (multiplying LTV), the other reduces CAC (dividing into the same LTV). Use the [Churn Rate Calculator](/churn-rate-calculator/) to model how churn reduction affects your LTV:CAC.
What is the LTV:CAC benchmark for Indian SaaS companies?
Indian B2B SaaS companies targeting global enterprise markets are typically held to the same 3:1 benchmark as global SaaS. Indian SaaS companies selling to domestic SME markets often need to operate at higher ratios (4:1 or above) to compensate for shorter average customer lifespans (due to higher churn) and smaller average contract values that make each customer less valuable relative to fixed acquisition costs. Indian SaaS focused on the MSMEs segment often achieves this through very low CAC via product-led growth or channel partnerships rather than outbound sales.
How should I use the LTV:CAC ratio in growth planning?
The LTV:CAC ratio determines the maximum sustainable customer acquisition spend per customer, which in turn limits how aggressively you can scale paid acquisition. If LTV:CAC is 5:1 and you are targeting 3:1 as your floor, you have room to increase marketing spend by up to 66% before hitting the minimum acceptable ratio. Conversely, if it is at 2.5:1, you need to either reduce CAC, increase LTV through churn reduction or expansion revenue, or both before aggressively scaling acquisition. The ratio is a growth governor, not just a health metric.
How is the LTV:CAC ratio different from ROAS?
ROAS (Return on Ad Spend) measures revenue generated per rupee of advertising spend, typically over a short window (campaign period or first purchase). LTV:CAC is a lifetime measure that captures the full customer value over their entire relationship with the business, net of all acquisition costs including sales, not just advertising. ROAS is a channel-level metric useful for optimising ad campaigns; LTV:CAC is a business-level metric useful for evaluating overall growth model sustainability. A high ROAS campaign can still produce customers with poor LTV:CAC if those customers churn quickly.