Cohort Retention Calculator

How to use Cohort Retention Calculator

Each supplied retained count divides by its positive cohort size. Aggregate periods weight only cohorts with an observed count at that age. Returning-active counts may rise; survival counts may not rise between observed periods.

1. Enter json cohort counts.
2. Choose the stated convention and check the units and supported model.
3. Calculate, inspect the result, then copy or download it.

Good to know

• JSON cohorts {name,size,retained:[count or null]}, at most100cohorts and36post-start periods. Counts are whole, within size; null means unobserved. No identifiers or automatic tracking.
• Runs locally. Text/JSON fields are capped at30,000 characters; stricter page-specific and numeric-string limits also apply. Numeric inputs are bounded to magnitude1e15 and nonzero magnitude at least1e-100 unless an exact-string mode states otherwise. Approximate summaries use12 significant digits; CSV numeric cells retain the complete stored value and potentially formula-like string cells gain a protective apostrophe; unsupported, non-finite or detected underflow states return an error.
• Educational user-assumption arithmetic only. No live prices, laws, tax rules, quotes or financial advice.