About Us
Online Medical Tools is a free resource providing evidence-based medical calculators and health tools. Our mission is simple: make health information accessible, accurate, and easy to understand.
Who runs this site
Online Medical Tools is built and run by Wonsuk Choi. He is not a clinician and not a licensed healthcare provider. Each calculator is built from the published formula, scoring system, or clinical guideline cited on its page, so you can check the result against the original source.
What you'll find here
The calculators span a broad range of specialties: cardiology, nephrology, endocrinology, pulmonology, hematology, gastroenterology, dermatology, rheumatology, orthopedics, neurology, oncology, obstetrics, pediatrics, geriatrics, emergency medicine, infectious disease, mental health, and general body metrics and nutrition. Each one is built to answer a single, specific clinical question — a dose, a risk score, a lab-value interpretation — rather than trying to be a general-purpose symptom checker.
Our Principles
- Free to use. Every calculator on the site is free and usable without creating an account. An account is only needed if you want to save a result to your history or come back to it later.
- Privacy first. Every calculation runs entirely in your browser — your inputs are never sent to a server just to compute a result. Your account only holds data you choose to save, like a favorited calculator or a saved result log. Our Privacy Policy explains what analytics we use.
- Evidence-based. Our formulas come from peer-reviewed medical literature and established clinical references.
- Transparent. We show the formulas we use and explain what each result means.
How the calculators work
Each tool implements a specific published formula or clinical scoring system — things like the Cockcroft-Gault equation for creatinine clearance, the Revised Cardiac Risk Index, or the Mifflin-St Jeor equation for resting energy expenditure. Where a tool is based on a named clinical reference, we cite it directly on the tool's page so you can check the source yourself rather than take our word for it. The math runs client-side in your browser using standard JavaScript arithmetic — there's no server-side model or AI involved in producing a number, just the formula itself.
Who this is for
Online Medical Tools is built for anyone who wants a quick, sourced answer to a specific clinical calculation — patients trying to understand a number from a recent lab result or doctor's visit, students studying clinical formulas, and clinicians who want a fast second check alongside their own judgment. It's a reference tool, not a diagnostic one: a calculator result is a starting point for a conversation with a qualified healthcare provider, not a replacement for one.
Disclaimer
The tools and information provided on this website are for educational and informational purposes only. They are not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions you may have regarding a medical condition.
Contact
Have a question, suggestion, or feedback? We'd love to hear from you. Visit our contact page to get in touch.