aibizhub
Structured methodology As of 2026-04-24

How Churn & Retention Calculator works

What the tool assumes, what data it pulls from, and what it cannot tell you.

1. Scope

Estimates recovered customers and revenue lift when monthly churn improves. It illustrates the sensitivity of LTV to churn; it is not a retention-programme design tool.

2. Inputs and outputs

Inputs

  • customers number
  • arpu number (currency/mo)
  • currentChurn percent (monthly)
  • targetChurn percent (monthly)

Outputs

  • currentLtv

    arpu / currentChurn.

  • targetLtv

    arpu / targetChurn.

  • ltvLift

    targetLtv − currentLtv.

  • recoveredCustomersYearOne

    Customers × (currentChurn − targetChurn) × 12.

Engine source: src/lib/churn-retention-calculator/engine.ts

3. Formula / scoring logic

current_ltv = arpu / current_churn
target_ltv  = arpu / target_churn
ltv_lift    = target_ltv - current_ltv

4. Assumptions

  • Churn is memoryless (exponential decay). Real SaaS retention curves are often logarithmic, giving longer tail than this formula suggests.
  • ARPU is flat; no expansion-revenue tailwind.
  • The recovered-customer figure is a steady-state difference, not a behavioural projection.

5. Data sources

6. Known limitations

  • The widely-cited Reichheld "5% retention lift = 25–95% profit lift" claim is context-dependent and not peer-reviewed. We do not use it as a benchmark. Consult the underlying Harvard Business School working paper directly if needed.
  • Treats logo churn and revenue churn as equivalent; they diverge for products with tiered pricing.

7. Reproducibility

Input
customers = 1000, arpu = $30, currentChurn = 6%, targetChurn = 4%.

Expected output
current_ltv = $500, target_ltv = $750, ltv_lift = $250, recoveredCustomers year 1 = 240.

8. Change log

  • 2026-04-24 methodology page first published.
Business planning estimates — not legal, tax, or accounting advice.