SaaS Revenue Estimator
MRR, ARR, and a churn-adjusted revenue projection for your SaaS business.
How this is calculated
MRR is customers × ARPU; ARR is MRR × 12. The 12-month projection compounds your churn rate monthly against the existing customer base, with no new customers assumed. Customer LTV is ARPU divided by churn rate — the standard shorthand estimate of total revenue per customer over their lifetime.
Churn compounds faster than most people expect, because each month's loss applies to an already-reduced base rather than the original one. A 2% monthly churn rate might sound negligible, but compounded over 12 months it works out to roughly 22% of starting revenue lost by year end (1 − 0.98¹²) — not the 24% a simple multiplication would suggest, and a meaningfully large number for what looks like a small monthly figure. This is exactly the effect the "12-month projection" above visualizes. For the acquisition-cost side of the same customer economics, see the Customer LTV calculator, and for how your cash position holds up while growing or shrinking, see the Startup Runway calculator.
Frequently asked questions
- Why does the 12-month projection go down?
- It models your existing customer base with no new customers added — just how much of today's MRR survives churn each month. It's a useful "what happens if growth stalls" view, not a forecast that assumes you'll keep acquiring customers.
- How is customer LTV calculated?
- ARPU divided by monthly churn rate — the standard shorthand LTV formula, which assumes a constant churn rate and no discounting. It approximates the total revenue a typical customer generates over their entire lifetime with you.
- What does "months to double revenue" mean here?
- It reframes your churn rate as a symmetrical growth rate — if you were gaining customers at the same rate you're currently losing them (instead of churning), this is roughly how long it would take to double your revenue.
- Can I use this in my own app?
- Yes — every calculator on Stupidly Clever has a matching REST API and MCP tool that runs the same underlying logic.
- What is ARR vs MRR?
- MRR (Monthly Recurring Revenue) is your predictable revenue for a single month. ARR (Annual Recurring Revenue) is simply MRR × 12 — a normalized annual figure commonly used for higher-level reporting, valuation multiples, and comparing SaaS businesses of different sizes.
- What is a good net revenue retention (NRR) rate?
- NRR above 100% means expansion revenue (upgrades, upsells) from existing customers outpaces revenue lost to churn and downgrades — a strong sign of a healthy business. Best-in-class SaaS companies often report NRR of 110–130%+; anything consistently below 100% means the existing customer base is shrinking in revenue terms even before counting new sales.
- How does churn compound over time?
- Because churn applies to whatever remains each month, a 2% monthly churn rate doesn't simply add up to 24% annual loss — it compounds to roughly 22% annual revenue loss (1 − 0.98¹²), since each month's churn is applied to an already-shrunken base. Higher monthly churn rates compound to disproportionately larger annual losses.
- What is expansion MRR?
- Expansion MRR is additional recurring revenue from existing customers — upgrades to a higher plan, add-on purchases, or seat/usage increases — as distinct from new MRR from newly acquired customers. Strong expansion MRR is what drives net revenue retention above 100%.