Free Online Epidemiologic and Statistical Calculators
Below is a list of free online epidemiologic and statistical tools and calculators which were published in the September 2026 issue of the EpiMonitor (47:9, pp 28-29). These are free online programs and can be useful for a number of purposes:
1. In teaching epidemiology and biostatistics, students can use these simple calculators and focus on the interpretation of the results. Sometimes when students need to write programs to perform calculations, such with R or SAS, the focus is on the programming and less on interpretation.
2. For analyzing data, sometimes raw data are not available and these calculators provide a simple was to perform the analysis. Note that most statistical programs can deal with reading summary data but frequently this takes more time than just plugging the summary data in a calculator.
3. Some calculators provide statistical analysis output that might not be available in some statistical programs.
I have used many of these programs over the years and used ChatGPT to identify other similar programs which are in the list below. Let me know if of your thoughts on these programs and if you know of the useful programs. Further down are new additions to the list.
1 OpenEpi
Epidemiology, 2×2 tables, stratified analysis, rates, proportions, diagnostic tests, sample size/power, matched case-control, ANOVA, dose-response
Epidemiology, epidemiologic/biostatistical calculators implemented in Google Sheets; sample size, analysis, and power (Beta version)
Epidemiology, 2×2 and stratified analysis, prevalence, diagnostic tests, cohort/case-control sample size, surveillance, pooled testing
Epidemiology / biostatistics, sample size, CIs, hypothesis tests, stratified analysis, CSV dataset analysis, graphics
Epidemiology, attack rates, OR/RR, DALYs, vaccine efficacy, screening test performance (Se/Sp/PPV/NPV), an SIR/SEIR epidemic simulator, and a general biostatistics suite (sample size, t-test, chi-square, ANOVA)
Epidemiology, stratified analysis (Mantel-Haenszel), R x C tables, SMR, matched case-control, dose-response, WHO child-growth standards, and other statistics
Epidemiology / biostatistics, design effect, cluster/stratified sample size, DALYs, PAF, standardization, VE, NNT/NNH, Poisson regression, meta-analysis
8 Wepisia
Epidemiology, OpenEpi-derived calculations plus epidemic simulation, mapping and in-browser R, in French
Medical statistics, means, proportions, rates, RR, OR, NNT, diagnostic tests, ROC, sample size/power
Biostatistics, fisher exact, chi-square, McNemar, proportion CI, NNT, t tests, regression, distributions
Sample size / clinical research, proportions, means, RR, diagnostic tests, clustered designs, logistic regression, survival, precision
12 ClinCalc
Clinical statistics, sample size, power, NNT, OR-to-RR conversion, fragility index
13 SRUC Sample Size Calculator
Veterinary epidemiology, prevalence estimation, disease detection and epidemiologic sample-size calculations
General statistics, t tests, ANOVA, chi-square, Fisher exact, proportions, correlation, nonparametric tests, regression, power
15 VassarStats
General statistics, t tests, contingency tables, proportions, ANOVA, regression, correlation and other statistical procedures
***New Additions*************************************************
Shiny EpiTools Added 9/28/2026
Epi and Bios tools, sample size, sampling, simple data analysis, distributions, diagnostic tests, thanks to Catriona Mackenzie.
FreeStatisticalTools Added 10/20/2026
As of this writing there are 92 tools; can import data. Tools include: Sample size and power calculations; Categorical data analysis; Survival analysis; Descriptive analysis; Graphs; Nonparametric tests; Correlation and Regression; Bayesian statistics; Reliabiility and agreement; Multivariate analysis; Structural equation modeling.
MetricGate Added 10/20/2026
This is a monster of a progam!!! A comprehensive, browser-based statistical analysis platform offering more than 8,600 R-powered calculators covering epidemiology, biostatistics, regression, survival analysis, sample size, and numerous other methods. Includes dataset import, AI-assisted analysis, customizable calculators, and access to underlying R code. Free and paid versions are available.
Statulator https://statulator.com/ Added 10/21/2026
Statulator is a free on-line statistical calculator that conducts statistical analyses, interprets the results, and makes suggestions for presenting them in reports, journal articles and dissertations.
MedCalc https://www.medcalc.org/en/calc/ Added 10/21/2026
MedCalc provides online tools for sample size calculations, statistical tests, and post-hoc power analysis.
Kevin S.
Epi.Center.Org@gmail.com
https://sites.google.com/view/epi-centre-org
https://www.linkedin.com/in/kevin-s-phd-0b38902/
Links to Epidemiology/Biostatistics/Statistics-Related sites
Epidemiology/Biostatistics Software sites
OpenEpi - free online epidemiologic/statistical calculator - see also "OpenEpi" tab at this Epi.Centre website: www.OpenEpi.com
OpenEpiSheets - a free online epidemiologic/statistical calculator similar to OpenEpi based on Google Sheets - see also "OpenEpiSheets" tab at this Epi.Centre website: https://sites.google.com/view/epi-centre-org/openepisheets
An adaptation of OpenEpi in French with additional features - Wepisia - « La connaissance est comme un baobab : une seule personne ne peut l'embrasser. » L'expertise de OpenEpi réimaginée: https://wepisia.vercel.app/
EpiCalc - free online epidemiologic/statistical calculator: https://epidemiology-calculator.replit.app/
EpiPlus - free online epidemiologic/statistical calculator: https://epiplus.phtlab.org/ (added 9/4/2026)
Epi Info - free epidemiologic software for data entry and analysis - see also "Epi Info" tab at this Epi.Centre website: www.cdc.gov/epiinfo
Free online Epidemiology Course, ActivEpi Web - see also "ActivEpi" tab at this Epi.Centre website: www.ActivEpi.com
Betty Jung's Web Site: many epidemiology-related links: www.bettycjung.net
Brixton Health has various programs, including WINPEPI (PEPI-for-Windows): https://www.brixtonhealth.com/
Interactive Statistical Calculation Pages "Stat Pages" - many statistical programs/information: https://statpages.info/
StatSoft - "This page lists primarily statistical software, along with mapping, spreadsheets, database, stuff to do data analysis or management. All of the packages are free to use": https://sites.google.com/site/gsocialchange/statsoft
John Snow Website - link to a website at UCLA providing information on the "Father of Epidemiology" https://epi-snow.ph.ucla.edu/
Links to resources for SAS, SPSS, Stata, and R, as well as statistical analysis: https://osctr.ouhsc.edu/BERDDCR/SoftwareTraining (added 9/4/2026)
Free Epidemiology Books
Breslow NE, Day NE. Statistical Methods in Cancer Research Volume II: The Design and Analysis of Cohort Studies. IARC Scientific Publication No. 82, 1986. Free PDF available here:
Breslow NE, Day NE. Statistical Methods in Cancer Research Volume I: The Analysis of Case-Control Studies. IARC Scientific Publication No. 32, 1980. Free PDF available here:
Basic Epidemiology, 2nd Edition by Bonita et al.: https://iris.who.int/bitstream/handle/10665/43541/9241547073_eng.pdf
Epidemiology for the Uninitiated - BMJ: https://www.bmj.com/about-bmj/resources-readers/publications/epidemiology-uninitiated
CDC's Principles of Epidemiology in Public Health Practice, 3rd Edition: https://stacks.cdc.gov/view/cdc/6914
Gordis Epidemiology by Celentano and Szklo, 6th Ed.: https://dl.konkur.in/2022/12/Epidemiology2019-%5Bwww.konkur.in%5D.pdf
Clinical Epidemiology - The Essentials, 5th Ed., by Fletcher et al.:
Epidemiology by Charlotte Baker: https://open.umn.edu/opentextbooks/textbooks/1541
Foundations of Epidemiology by Marit L. Bovbjerg: https://open.oregonstate.education/epidemiology/
An Introduction to Epidemiology for Health Professionals by Olsen et al.: https://www.academia.dk/BiologiskAntropologi/Epidemiologi/PDF/An_Introduction_to_Epidemiology_for_Health_Professionals.pdf
Digital Epidemiology by Marcel Salathé: https://www.digitalepibook.com/
Principles of Epidemiology: A Primer - CHRISTY N BAZAN, PEDRO CURI HALLAL, RACHEL A. HOOPSICK, SHEENA MARTENIES, ANDIARA SCHWINGEL, AND RAFAEL M. TASSITANO: https://iopn.library.illinois.edu/books/windsor-downs/catalog/book/32 (added 4/15/2026)
SAS for Epidemiologists: Applications and Methods - Charles DiMaggio: https://link.springer.com/book/10.1007/978-1-4614-4854-9 (added 4/15/2026)
Essentials of Epidemiology in Public Health, 4th Ed - Anne Aschengrau and George R. Seage: https://www.academia.edu/43690544/ESSENTIALS_OF_FOURTH_EDITION?email_work_card=view-paper (added 8/24/2026)
Free Biostatistics/Statistics Books
Fundamentals of Biostatistics, 7th Ed., Rosner: https://www.unilus.ac.zm/lms/e-books/books/Basic_Sciences/Behavioural%20sciences%20and%20public%20health/Fundamentals%20of%20Biostatistics%20%287th%20Edition%29.pdf
A link to 10 free statistics books: https://medium.com/@vespinozag/10-statistics-books-that-you-should-download-open-access-1655780a73fc
Link to 18 free SAS books, including: Bayesian Methods with SAS; Forecasting with SAS; SAS Programming for R Users; Exploring Modern Regression Methods Using SAS: https://support.sas.com/en/books/free-books.html
Sample size determination in health studies : a practical manual / S. K. Lwanga and S. Lemeshow: https://iris.who.int/items/9c2e5da4-3785-4fec-9dbc-841e4ae0d98c (added 9/1/2026)
Free monthly epidemiology newsletter
The Epidemiology Monitor Newsletter: https://epimonitor.net/
Manuscripts
Kevin S, Mary G. Improved Point and Confidence Limit Estimates for Attributable and Prevented Fraction Among Exposed. Epi.Centre, 2025. drive.google.com/file/d/11j16PGXkGKmicVgrayJJJ8-KdazxlTB6/view?usp=drive_link (A link to the Excel Spreadsheet can be found in the Excel tab)
Kevin S, Mary G. Estimation of risks, risk ratio and difference with confidence limits from unmatched cumulative case-control studies. Epi.Centre, 2025. drive.google.com/file/d/1334jkEkACIOisq5rAsCy2ptmIoEsMszv/view?usp=drive_link