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Model LTV, churn, CAC payback, and LTV:CAC for your SaaS.
📐 Formulas: Lifetime = 1 / churn · LTV = ARPU × gross margin / churn · LTV:CAC < 1 is unsustainable, 1–3 is OK, > 3 is great · CAC payback = CAC / (ARPU × margin) · NRR ≈ (1 + growth − churn). With 0% churn the lifetime is unbounded, shown as ∞. Real NRR also includes expansion, contraction, and reactivation revenue.
This SaaS metrics calculator turns a handful of inputs — ARPU, gross margin, churn, CAC, growth, and customer count — into the numbers founders and investors actually watch: customer lifetime, LTV, LTV:CAC ratio, CAC payback, churned MRR, and a simplified net revenue retention hint. It runs entirely in your browser; nothing is sent anywhere.
With a constant monthly churn rate, a customer survives 1 / churn months on average — 5% churn means a 20-month expected lifetime. Multiplying by monthly gross profit per customer gives LTV = ARPU × gross margin ÷ churn. Using gross margin (not raw revenue) matters: at 80% margin, only $0.80 of every revenue dollar is available to repay acquisition costs. At 0% churn the lifetime is mathematically unbounded, which the tool shows as ∞.
The LTV:CAC ratio is the classic unit-economics test: below 1 you lose money on every customer, 1–3 is workable, and above 3 is considered healthy growth. CAC payback tells you how many months of gross profit are needed to recover acquisition spend — under 12 months is a common benchmark. The churned-customers and lost-MRR cards translate an abstract percentage into the actual number of accounts and revenue walking out the door each month.
These formulas assume churn and ARPU stay constant over the lifetime — real cohorts decay non-linearly, and early churn is usually higher than steady-state. The NRR hint (1 + growth − churn) is a simplification: true net revenue retention also counts expansion, downgrades, and reactivations within the existing base. Use these numbers for quick sanity checks and pitch-deck math, not as a substitute for cohort analysis on real billing data.
The SaaS LTV Calculator lets you figure out ltv calculatorinstantly, without reaching for a spreadsheet or doing the math by hand. Whether you're planning a budget, checking a loan, or working through homework, the tool applies the correct formula behind the scenes and shows the result the moment you enter your numbers.
Unlike a static chart or table, this calculator adapts to your exact inputs. You can adjust any value and see the outcome update in real time, which makes it easy to compare scenarios — for example, "what if the rate were 1% lower?" or "what if I paid an extra $50 a month?"
Common uses: people reach for this tool when they need to find a saas customer lifetime value calculator, ltv to cac ratio calculator, churn rate impact on revenue, or cac payback period calculator.
Browser-based tools like this one have a few real advantages over installed software or manual methods:
The SaaS LTV Calculator is based on the following formula:
LTV = ARPU / churn LTV:CAC = LTV / CAC
Variables: LTV = Customer lifetime value ($) ARPU = Average revenue per user per month ($) churn = Monthly churn rate (decimal, e.g. 0.04 for 4%) CAC = Customer acquisition cost ($) LTV:CAC = Ratio of lifetime value to acquisition cost
Customer lifetime value equals average revenue per user divided by the churn rate (average lifetime ≈ 1/churn). LTV:CAC compares value to acquisition cost; 3:1 is a common target.
Worked example: Step 1: ARPU = $40/month, monthly churn = 4% → 0.04. Step 2: LTV = 40 / 0.04 = $1,000 (average customer lifetime = 1/0.04 = 25 months). Step 3: CAC = $250 → LTV:CAC = 1,000 / 250 = 4:1. Result: a 4:1 ratio clears the 3:1 target, so acquisition spend is efficient at these churn levels.
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