Free Online Epidemiologic and Statistical Calculators
Here is a list of free online epidemiologic and statistical calculators. These are free programs that are available online through use of a browser and therefore do not require the installation of software. These programs 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 get the answers, such R or SAS, the focus is on the programming and less on interpretation.
2. For analyzing data, sometimes the raw data is 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.
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 modules (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, odds ratios and other epidemiologic calculations
Epidemiology
Stratified analysis, SMR, matched case-control, 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
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
Clinical statistics
Sample size, power, NNT, OR-to-RR conversion, fragility index
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
General statistics
t tests, contingency tables, proportions, ANOVA, regression, correlation and other statistical procedures
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