SaaS unit economics calculator
Four inputs, three answers: what a customer is worth, how fast you earn back acquisition cost, and whether the ratio holds up.
LTV : CAC
8.2×
Healthy — each customer returns at least 3× what it cost to acquire.
- Monthly gross profit per customer
- $36.75
- Expected lifetime
- 33.3 months
- Lifetime value (gross profit)
- $1,225
- CAC payback
- 4.1 months
Want this from real data, every day? Connect Stripe and get it automatically →
The formulas
Using gross profit rather than revenue keeps these honest for products with real cost-to-serve — especially AI products, where margin can be well below classic SaaS.
Reading the result
- An LTV:CAC of 3× or more is a common rule of thumb for healthy acquisition.
- Payback under 12 months keeps cash needs manageable for most early-stage companies.
- LTV is very sensitive to churn; small churn improvements change it a lot.
Definitions: LTV, CAC, payback period.
Frequently asked questions
Why use gross margin in LTV?
Revenue-based LTV ignores the cost of serving the customer. Gross-profit LTV shows what the customer actually contributes.
What if churn is zero?
Lifetime becomes undefined, so the calculator shows a dash. Use a conservative churn estimate instead.
Related tools
See your real margin in five minutes.
Connect Stripe and your cost providers with read-only access. Free for two connections — no card required.