Kaplan-Meier Survival Calculator
Calculate an observed product-limit survival/reliability curve, risk table, median and Greenwood standard errors from event/censor times.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Order event/censor times, update survival with conditional event fractions and remove tied censors after same-time events.
S(t)=product over event times of (1−events/at-risk count)
Worked example
Four observations at times 1 event, 2 censored, 3 event and 4 event give survival 0.75, 0.75, 0.375 and 0. The observed median is time 3.
Assumptions and input details
Up to 500 subjects/items, nonnegative follow-up times and event flags exactly 0 or 1. Independent units and noninformative right censoring are assumed. Events occur before same-time censors are removed. Standard error is not reported at zero survival. There is no left truncation, confidence interval or projection beyond observed follow-up; this is not an individual clinical prognosis.
References: NIST: empirical Kaplan–Meier reliability estimation
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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