Kaplan-Meier Survival Analysis Online
Estimate survival over time from data with censored cases, compare groups with the log-rank test, and plot Kaplan-Meier curves.
Updated · By Bibin XavierData 160 × 6
| Patienttext · 160 levels | Treatmenttext · 2 levels | Agenumeric | Stagenumeric · coded | Time_Monthsnumeric | Eventnumeric · coded |
|---|---|---|---|---|---|
| P001 | Standard | 71 | 1 | 10.5 | 0 |
| P002 | New | 71 | 3 | 23.9 | 1 |
| P003 | Standard | 70 | 2 | 40 | 1 |
| P004 | New | 68 | 3 | 3.2 | 1 |
| P005 | Standard | 72 | 3 | 18.1 | 0 |
| P006 | New | 55 | 1 | 9.1 | 1 |
| P007 | Standard | 73 | 3 | 4.6 | 1 |
| P008 | New | 66 | 3 | 32 | 0 |
Variables and options
Results
160 rows · example dataCase summary and median survival
| Group | N | Events | Censored | Median survival | Survival at last event |
|---|---|---|---|---|---|
| New | 80 | 30 | 50 | 38.1 | .444 |
| Standard | 80 | 44 | 36 | 23.0 | .234 |
Log-rank (Mantel-Cox) test
| Group | Observed events | Expected events |
|---|---|---|
| New | 30 | 40.43 |
| Standard | 44 | 33.57 |
Note. χ²(1) = 5.97, p = .015.
Interpretation
Survival differed significantly between groups. New: median 38.1; Standard: median 23.0.
Kaplan-Meier survival curves
Survival table: New
| Time | At risk | Events | Survival | SE | 95% CI |
|---|---|---|---|---|---|
| 0.5 | 80 | 1 | .988 | .012 | [.963, 1.000] |
| 1.6 | 79 | 1 | .975 | .017 | [.941, 1.000] |
| 2.2 | 78 | 1 | .963 | .021 | [.921, 1.000] |
| 2.7 | 77 | 1 | .950 | .024 | [.902, .998] |
| 3.0 | 76 | 1 | .938 | .027 | [.884, .991] |
| 3.2 | 75 | 1 | .925 | .029 | [.867, .983] |
| 3.3 | 74 | 1 | .913 | .032 | [.851, .974] |
| 3.8 | 73 | 1 | .900 | .034 | [.834, .966] |
| 4.5 | 72 | 1 | .888 | .035 | [.818, .957] |
| 4.9 | 71 | 1 | .875 | .037 | [.803, .947] |
| 9.1 | 63 | 1 | .861 | .039 | [.785, .937] |
| 9.3 | 62 | 1 | .847 | .041 | [.767, .927] |
| 9.7 | 60 | 1 | .833 | .042 | [.750, .916] |
| 10.2 | 58 | 1 | .819 | .044 | [.732, .905] |
| 11.3 | 56 | 1 | .804 | .046 | [.715, .893] |
| 14.1 | 53 | 1 | .789 | .047 | [.696, .881] |
| 17.6 | 44 | 1 | .771 | .049 | [.674, .868] |
| 17.7 | 42 | 1 | .753 | .052 | [.652, .854] |
| 21.1 | 38 | 1 | .733 | .054 | [.627, .838] |
| 21.4 | 37 | 1 | .713 | .056 | [.603, .823] |
| 22.4 | 36 | 1 | .693 | .058 | [.580, .806] |
| 23.3 | 33 | 1 | .672 | .060 | [.555, .789] |
| 23.9 | 32 | 1 | .651 | .061 | [.531, .772] |
| 24.2 | 31 | 1 | .630 | .063 | [.507, .754] |
| 24.8 | 30 | 1 | .609 | .064 | [.483, .735] |
| 25.7 | 28 | 1 | .587 | .066 | [.459, .716] |
| 27.3 | 26 | 1 | .565 | .067 | [.434, .696] |
| 37.4 | 14 | 1 | .525 | .073 | [.381, .668] |
| 38.1 | 13 | 1 | .484 | .078 | [.331, .637] |
| 39.4 | 12 | 1 | .444 | .081 | [.285, .603] |
Note. Greenwood standard errors.
How to cite this tool
Using these results in a thesis, journal article, report or class assignment? Please cite this free tool so others can find it. It keeps the site free.
APA 7
Xavier, B. (2026). Kaplan-Meier Survival Analysis Online [Web application]. FreeStatisticalTools.com. https://freestatisticaltools.com/kaplan-meier-survival-analysis/
BibTeX
@software{xavier_kaplanmeier_2026,
author = {Xavier, Bibin},
title = {Kaplan-Meier Survival Analysis Online},
publisher = {FreeStatisticalTools.com},
year = {2026},
url = {https://freestatisticaltools.com/kaplan-meier-survival-analysis/},
note = {Web application}
}Suggested sentence for your methods section: “The analysis was carried out with the free Kaplan-Meier Survival Analysis Online tool on FreeStatisticalTools.com (Xavier, 2026).”
What is Kaplan-Meier survival analysis?
The Kaplan-Meier method estimates the probability of surviving past each time point from data that include censored cases. The log-rank test compares survival curves between groups.
When to use Kaplan-Meier survival analysis
Use it for time-to-event data where some cases have not had the event by the end of follow-up (censored), such as time to death, relapse or customer churn.
Assumptions
- Censoring is unrelated to the chance of the event.
- Survival chances are the same for cases recruited early and late.
How to set up your data
One row per case: a time column, an event column (for example 1 = event, 0 = censored) and an optional group column.
How to use this tool
- Enter your data. Paste columns from Excel, Google Sheets or SPSS with variable names in the first row, or upload a CSV or Excel file. The example data shows the expected layout.
- Choose the variables. Select the time, event status, value meaning the event occurred and compare groups.
- Read the results. Results update automatically. Read the plain-English interpretation, then use Copy table to paste APA-style tables into Word and Copy for the results sentence.
How to report Kaplan-Meier survival analysis in APA style
“Median survival was 31.2 months with the new treatment and 18.4 with standard care, log-rank χ²(1) = 6.84, p = .009.”
Frequently asked questions
What is censoring?
A case is censored when follow-up ends before the event occurs, for example a patient still alive at the end of the study.
What is median survival?
The time at which the estimated survival probability falls to 50%. If the curve never reaches 50%, the median is not reached.
What does the log-rank test compare?
It compares observed and expected events in each group over the whole follow-up, testing whether the survival curves differ.
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