Six numbers about your SaaS give you the metrics investors and founders watch: MRR, ARR, customer lifetime, LTV, LTV:CAC, CAC payback, and the customer count where churn cancels out your growth.
How to use the SaaS metrics calculator
- Enter paying customers, average revenue per customer and monthly churn.
- Add new customers per month, what each costs to acquire, and your gross margin.
- Read the results and the health checks below them.
The formulas
MRR = customers × average revenue. LTV = average revenue × gross margin ÷ monthly churn. CAC payback = CAC ÷ (average revenue × gross margin). Lifetime = 1 ÷ churn. The plateau = new customers per month ÷ churn.
Why churn decides everything
At 5% monthly churn, a customer stays 20 months on average. Halve churn and you double LTV and the size you can grow to without spending more on acquisition. For a small SaaS, cutting churn is often cheaper than finding new customers.
Healthy ranges
LTV at least 3× CAC, CAC paid back within 12 months, and monthly churn under 3% for small-business customers. Early products often miss these; the point is to see which lever moves the most.