Retention Curve

Category: Growth & Engagement · Level: Mid · Also called: Retention chart

TL;DR

A chart showing what fraction of a cohort is still active week-by-week or month-by-month after sign-up.

A retention curve plots time on the x-axis and the percentage of an original cohort still active on the y-axis. The shape of the curve diagnoses the business: a curve that decays to zero means no PMF; a curve that flattens at a stable plateau means real, sticky usage; a curve that turns upward (the 'smile') means net-negative churn and is the strongest signal a product can show.

Investors read retention curves before any other metric on the Traction slide. A strong curve compensates for weak top-line growth; weak curves invalidate strong top-line growth.

Formula

Retention(d) = (Cohort users active on day d ÷ Cohort size) × 100%

  • Cohort size — Number of users who first signed up on day 0 of the cohort
  • d — Number of days after sign-up

A 'flattening' curve (e.g. 25% at D30, 24% at D60, 24% at D90) signals product-market fit; a curve that keeps falling does not.

Worked example

A consumer app's January cohort: D1 retention 60%, D7 32%, D30 18%, D60 17%, D90 17% — the curve flattens around 17%, indicating roughly 1-in-6 users become long-term actives.

Common pitfalls

  • Showing average retention instead of cohort retention.
  • Rolling cohorts together to mask declining retention over time.
  • Truncating the chart at week 4 to hide later decay.

When this shows up in a pitch deck

The Traction slide should include a cohort retention chart, not just a 'users over time' chart.

Related terms

  • Cohort Analysis — Grouping users by sign-up period and tracking each group's behavior over time to spot trends invisible in aggregate metrics.
  • Logo Churn — The percentage of customers (logos) who cancel in a given period, regardless of how much revenue they represented.
  • Revenue Churn — The percentage of recurring revenue lost from existing customers in a period through cancellation or downgrade.
  • Net Revenue Retention — The percentage of recurring revenue retained from a cohort after one year, including expansion, contraction, and churn.
  • Product-Market Fit — The point at which a product satisfies a market well enough that demand pulls the company forward instead of the team pushing it.

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