What this is for: Two-group Kaplan–Meier survival curves and median survival from per-animal time/event-or-censor data.
The formula: S(t) = Π over event times of (1 − events ÷ animals at risk)
How to use:
- Name the two groups, then enter each animal on its own line as: time status — time in days, status 1 for an event/death or 0 for censored.
- Enter or update the sorted event-time list for the KM table so it covers your data's event times — the table and curves are evaluated at those times.
- Read the KM table (at risk, events and survival S for each group at each time) and the step survival chart.
- Read each group's median survival; 'not reached' means survival stayed above 0.5 at all listed times.
Kaplan–Meier Survival — two groups
Per animal: time (days) and status (1 = event/death, 0 = censored), one animal per line as time status. Survival S(t) = product over event times of (1 − events/at-risk). Median survival = first time S ≤ 0.5.
Animals (A / B) /
Survival A at first event time
Median survival — group A (days)
Median survival — group B (days)
Prefer to work offline or keep a copy? The download link is right below.
Download the Kaplan–Meier Survival workbook (.xlsx)
Download the Kaplan–Meier Survival workbook (.xlsx)
Notes & limits (from the workbook): Status must be 1 (event/death) or 0 (censored). The KM table is evaluated at the event-time list shown — in the workbook those times are pre-filled from the example, so update the list if your event times differ. Median survival is the first listed time at which S ≤ 0.5; if survival never falls to 0.5 the median is not reached. No log-rank test is included, matching the workbook.