Customer lifetime: definition, formula, and how to estimate it

Customer lifetime explained: how to estimate lifetime from churn, why the simple formula can be wrong, and how to improve the estimate with cohorts.

Updated 2026-01-23

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Definition

Customer lifetime is how long customers remain active before churn. Lifetime matters because it drives LTV and payback viability.

Simple formula (shortcut)

Customer lifetime (months) ~ 1 / monthly churn rate

Worked example

If monthly churn is 3%, the simple estimate is lifetime ~ 1 / 0.03 ~ 33.3 months. This is useful for planning but can be wrong if churn changes over tenure.

Why the shortcut breaks

  • Churn is usually higher early and lower later (tenure effects).
  • Segments behave differently (SMB vs enterprise).
  • Expansion and downgrades change revenue lifetime vs logo lifetime.

A better approach

  • Use cohort retention curves (logo and revenue) to measure observed survival over time.
  • Estimate LTV by summing gross profit over the cohort curve.
  • Track churn drivers and reduce early churn (activation and onboarding).

Segmented lifetime planning

  • Estimate lifetime separately for SMB vs enterprise; churn curves differ.
  • Use product usage tiers to separate low-usage churn from power users.
  • Recompute lifetime after pricing or packaging changes.

Lifetime data quality checks

  • Use a consistent churn definition (logo vs revenue) across periods.
  • Exclude paused or seasonal accounts if they are not true churn.
  • Align churn measurement to the same billing period (monthly vs annual).

FAQ

Should I use logo churn or revenue churn-
Use logo churn to estimate customer lifetime (accounts). Use revenue retention (GRR/NRR) to understand revenue lifetime when expansions exist.

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