Customer Lifetime Value Calculator — LTV:CAC Ratio Tool
Enter your ARPU, churn, margin, and CAC — get your ratio, payback period, investor readiness score, and a shareable scorecard. No signup.
Last reviewed: March 2026
How to Calculate Customer Lifetime Value for SaaS (and Your LTV:CAC Ratio)
Step 1: Enter your monthly ARPU and gross margin
Average Revenue Per User (ARPU) is your MRR divided by your total active customers. If you have $30,000 MRR and 100 customers, your ARPU is $300/month. Gross margin is the revenue remaining after hosting, payment processing, and direct support costs — for most SaaS businesses, this falls between 70% and 85%. Be conservative: include payment processing fees (typically 2–3%) and infrastructure costs that scale with customers.
Step 2: Set your monthly (or annual) churn rate — toggle between modes
Monthly churn is the percentage of customers who cancel each month. 2% monthly churn equals roughly 22% annual churn. Many founders track annual churn in board reports — use the Annual toggle and this calculator converts it to monthly automatically using the formula: monthlyChurn = 1 − (1 − annualChurn)^(1/12). The converted rate is displayed below the field so you can verify the math.
Step 3: Enter your Customer Acquisition Cost
CAC is the fully-loaded cost to acquire one paying customer. Include: paid advertising spend, sales team salaries prorated by deals closed, SDR time, demo costs, onboarding, and first-90-day customer success. Many founders underestimate CAC by 30–50% by excluding sales salary and onboarding costs. Use the CAC Decomposition panel in Advanced mode to break it down accurately by channel.
Step 4: Read your ratio on the gauge — the Fix-It panel tells you which lever to pull
The animated arc gauge displays your current LTV:CAC ratio across five zones: Critical (<1×), Recovering (1–2×), Approaching Target (2–3×), Healthy (3–5×), and Exceptional (>5×). The Fix-It Intelligence Engine below the inputs analyzes all four levers — churn, CAC, ARPU, and margin — and tells you which single change requires the smallest percentage improvement to reach the 3:1 benchmark.
Step 5: Compare scenarios and share your scorecard
The Scenario Matrix lets you compare your current numbers against two custom what-if scenarios side by side — useful for board prep or evaluating strategic options. When you're done, export a 1200×630 PNG scorecard to share in investor updates, Slack, or on Twitter.
The Customer Lifetime Value Formula (CLV) — Explained
Customer Lifetime Value (LTV) is the total gross profit a single customer generates over their entire relationship with your company. For subscription SaaS, it's modeled mathematically using three inputs:
Customer Lifetime Value
LTV = (ARPU × Gross Margin) ÷ Monthly Churn Rate
The area under the cohort revenue decay curve — what each customer is worth on day one.
LTV:CAC Ratio
Ratio = LTV ÷ CAC
How many dollars you earn per dollar spent acquiring a customer.
Payback Period
Payback = CAC ÷ (ARPU × Gross Margin)
Months until you recover your acquisition cost — the capital efficiency measure investors love.
Average Customer Lifespan
Lifespan = 1 ÷ Monthly Churn Rate
How many months an average customer stays before churning.
Example: ARPU $299, gross margin 78%, monthly churn 2%, CAC $1,200. LTV = ($299 × 0.78) ÷ 0.02 = $11,661. Ratio = $11,661 ÷ $1,200 = 9.7×. Payback = $1,200 ÷ ($299 × 0.78) = 5.1 months.
What Is CAC and How to Calculate It Accurately
Customer Acquisition Cost (CAC) is the fully-loaded cost to convert one prospect into a paying customer. Most founders undercount CAC by forgetting to include the time cost of sales and the ongoing cost of customer success in the first 90 days.
A fully-loaded CAC calculation includes: (1) Paid advertising spend allocated to new customer acquisition. (2) Sales and SDR salary costs prorated across closed deals — if your sales rep earns $8,000/month and closes 8 deals, that's $1,000/deal. (3) Onboarding and first-90-day customer success costs — support tickets, setup calls, and configuration time.
Enterprise SaaS companies routinely see CAC of $10,000–$50,000 because of long sales cycles and high-touch onboarding. This is acceptable when LTV is proportionally large. The ratio is what matters — not the absolute numbers.
The 3:1 Benchmark — Why It Matters
The 3:1 LTV:CAC ratio has become the de facto minimum threshold for healthy SaaS unit economics, cited by David Skok (Matrix Partners), OpenView, and SaaStr. Here's why it's meaningful:
At 1:1, you break even — but only in the LTV/CAC sense. You still have to cover overhead, R&D, and G&A on top of CAC, so the company is losing money overall. At 2:1, you have margin to cover overhead but little room for growth investment. At 3:1, you have healthy unit economics that can sustain investment in product, sales, and marketing while returning profit. Above 5:1, investors often say you're underinvesting in growth and should be spending more on acquisition.
The 3:1 number is a guideline, not a law. High-velocity PLG companies sometimes operate at 5:1+ with sub-6-month payback. Enterprise sales-led companies might be at 4:1 but with 18-month payback — still investor-grade. Always consider ratio AND payback period together.
Payback Period — The Capital Efficiency Metric
Payback period is how many months it takes to recover your CAC from a customer's gross margin contribution. Unlike LTV:CAC, which is an efficiency ratio, payback period is a cash flow metric — it tells you how long your capital is tied up before you see a return.
In a high-churn environment, a short payback period is essential because you need to recover CAC before the customer churns. If monthly churn is 5% and payback is 24 months, there's a significant risk that many customers churn before you break even on them.
Investor benchmarks: Series A investors typically want payback under 18 months. Payback under 12 months is the gold standard for efficient SaaS growth. Payback over 24 months raises questions about capital efficiency and increases reliance on external funding.
Series A Expectations — What Investors Actually Look For
Based on OpenView's 2024 SaaS Benchmarks report and publicly cited investor frameworks, here are the unit economics benchmarks Series A investors commonly apply:
Metric
LTV:CAC Ratio
Payback Period
Gross Margin
Monthly Churn
NRR
Series A Target
3:1 minimum
≤ 18 months
65%+ (70%+ preferred)
< 3% / month
100%+ (110%+ exceptional)
These numbers are averages and vary by segment. Enterprise SaaS (ACV > $50K) can operate with higher CAC, longer payback, and lower churn. Consumer SaaS needs sub-$30 CAC and payback under 6 months given high churn rates. Above, the Investor Readiness Badge grades your inputs against these benchmarks in real time.
Frequently Asked Questions
What is a good LTV:CAC ratio?
A good LTV:CAC ratio for SaaS is 3:1 or higher. This means your customers generate 3× more revenue over their lifetime than it cost to acquire them. Ratios below 1:1 mean you're losing money on every customer. Above 5:1 is exceptional. Most Series A investors require at least 3:1 before leading a round.
How is LTV calculated for SaaS?
LTV = (ARPU × Gross Margin) ÷ Monthly Churn Rate. Example: $299 ARPU, 78% margin, 2% churn → LTV = ($299 × 0.78) ÷ 0.02 = $11,661. This assumes constant ARPU and churn. In Advanced mode, this calculator adjusts for expansion MRR and support costs.
What does a 3:1 LTV:CAC ratio mean?
A 3:1 ratio means you earn $3 in lifetime gross profit for every $1 spent acquiring a customer. This is the widely-cited minimum healthy threshold. Below 3:1, your unit economics may not support scaling — you need to reduce CAC, raise ARPU, reduce churn, or improve gross margin.
How do I reduce my CAC?
The most effective levers: (1) Improve conversion rates on existing traffic — a 20% conversion improvement = 20% CAC reduction. (2) Invest in product-led growth — free trials and freemium cut sales cost. (3) Build referral programs — referred customers have 16–30% lower CAC. (4) Focus spend on highest-converting channels and cut the rest. Use the CAC Decomposition panel in Advanced mode to identify your biggest cost driver.
What's a healthy payback period?
Under 12 months is healthy for most SaaS. 12–18 months is acceptable for enterprise with large ACV. Over 24 months raises capital efficiency concerns. Series A investors typically want ≤18 month payback, and prefer under 12 months for growth-stage companies.
What LTV:CAC ratio do Series A investors expect?
Most Series A investors look for 3:1+ ratio combined with ≤18 month payback. Some use 5:1 as the bar for exceptional growth-stage companies. The trend matters too — investors want to see the ratio improving quarter over quarter, not just hitting the threshold once.
How do I improve my LTV:CAC ratio?
Four levers: (1) Reduce churn — often highest-impact, since churn compounds negatively. Cutting monthly churn from 4% to 2% doubles LTV. (2) Lower CAC — optimize conversion rates, invest in SEO, build referrals. (3) Raise ARPU — price increases, upsells, annual plan incentives. (4) Improve gross margin — reduce hosting costs, renegotiate payment processing. Use the Fix-It Intelligence Engine in this calculator to see which lever is most efficient for your specific numbers.