Resources for medical students
Free clinical tools, epidemiology references, biostatistics calculators, and study resources — built and curated by doctors for the next generation of clinicians.
Emergency Medicine
BLS Algorithm — Basic Life Support
Complete BLS algorithm following AHA 2020 guidelines. Step-by-step instructions for adults, children, and infants including CPR and AED use.
ACLS Algorithms — Advanced Cardiac Life Support
VFib/VTach, PEA/Asystole, Bradycardia, and Tachycardia management with full medication protocols. ACLS 2020 guidelines.
ASCVD Risk Calculator
10-year cardiovascular risk calculator using the Pooled Cohort Equations (AHA/ACC 2013). Calculates statin therapy thresholds.
Epidemiology
Incidence & Prevalence Calculator
Calculate incidence rate, prevalence, attack rate, and mortality rate. Essential for understanding disease burden in populations.
Odds Ratio & Relative Risk
2×2 contingency table calculator for OR, RR, ARR, NNT, and confidence intervals. Covers both case-control and cohort study designs.
Study Design Flowchart
Interactive decision tree to choose the right study design for any research question. RCTs, cohort, case-control, cross-sectional, and more.
Epidemiology Definitions
Searchable glossary of epidemiology terms — sensitivity, specificity, PPV, NPV, attributable risk, confounding, effect modification, and more.
Bias Cheat Sheet
Quick reference for selection bias, information bias, confounding, and effect modification. Includes examples from real studies and how to control for each.
Biostatistics
Sample Size Calculator
Calculate required sample sizes for clinical trials and observational studies. Supports proportions, means, and survival outcomes with power and alpha inputs.
Confidence Interval Calculator
Calculate 95% and 99% confidence intervals for means, proportions, odds ratios, and relative risk. Includes interpretation guidance.
Statistical Test Selector
Answer a few questions about your data type and research design — the tool recommends the correct statistical test and explains why.
Biostatistics Formula Sheet
Comprehensive formula reference for exams and research: sensitivity, specificity, LR+/LR−, NNT, Bayes theorem, survival analysis formulas.
Clinical Tools & Obstetrics
EDD Calculator — Estimated Due Date
Calculate estimated due date by LMP (Naegele's rule), conception date, or ultrasound. Displays gestational age and trimester at any point.
Developmental Milestones
Age-by-age developmental milestones for gross motor, fine motor, language, and social skills. Includes red flags and when to refer.
BMI Calculator
Body Mass Index with WHO classification, ideal weight range, and metabolic risk interpretation. Includes metric and imperial units.
Key Formulas — Quick Reference
| Measure | Formula | When to use |
|---|---|---|
| Sensitivity | TP / (TP + FN) | How well a test detects true positives (rules out disease when negative) |
| Specificity | TN / (TN + FP) | How well a test excludes true negatives (rules in disease when positive) |
| PPV | TP / (TP + FP) | Probability a positive test is a true positive (affected by prevalence) |
| NPV | TN / (TN + FN) | Probability a negative test is a true negative |
| Odds Ratio | (a×d) / (b×c) | Association measure for case-control studies |
| Relative Risk | [a/(a+b)] / [c/(c+d)] | Association measure for cohort and RCT studies |
| ARR | CER − EER | Absolute risk reduction — actual reduction in event rate with treatment |
| NNT | 1 / ARR | Number needed to treat — clinically meaningful measure of effect size |
| Incidence Rate | New cases / Person-time at risk | Disease frequency in a defined population over time |
| Prevalence | All cases / Population at risk | Disease burden at a point in time |
Full formula sheets with worked examples: Biostatistics Formula Tool →
For educational purposes only. Clinical tools on this site are intended as learning aids and reference resources. They do not replace clinical judgement, local protocols, or direct supervision. Always follow your institution's guidelines in practice.