Making Health Calculations Simple
Our free tools help people explore health measurements, conversions, and estimates. Their methods and limitations vary: a unit conversion, a screening score, and a lifestyle estimate should not be treated as the same kind of result.
Calculations on Your Device
Calculations run in your browser. Some tools can save entries on your device; our Privacy Policy explains local storage, ratings, and advertising.
Methods & Limitations
Some tools implement published formulas; others use simplified estimates. Inclusion on this site does not mean a tool has been clinically validated.
User Focused
Simple, intuitive tools designed for everyone, regardless of medical knowledge.
Meet Our Founders
Two Croatian developers revolutionizing access to health calculation tools
Entrepreneurial Vision & User-Focused Design
Jurica Šinko is a remarkable Croatian entrepreneur who became the youngest registered company director in Croatia at just 18 years old. His proven ability to identify user needs and create accessible digital solutions drives our mission to make health information and calculations available to everyone, regardless of their medical knowledge or technical expertise.
Building User-Centric Platforms
While still a high school student at Varaždin's Electromechanical School, Jurica identified market gaps and founded Kupi Key d.o.o. in March 2012. By 2014, the company had cleared over HRK 1 million in net profit, serving over 300,000 customers worldwide with a focus on accessibility and user experience.
Democratizing Health Information
His vision for Health Calculator Online is to break down barriers to health information. We believe everyone deserves access to reliable health calculation tools based on established medical research and guidelines, presented in an accessible, user-friendly format.
Our aim is to make health calculations easier to understand, with clear inputs, understandable results, and honest explanations of what a tool can and cannot tell you.
Technical Excellence & Health Data Expertise
Marko Šinko is a Croatian developer with exceptional programming abilities and a passion for creating accessible health information tools. His expertise in data processing, API integration, and algorithm development ensures that every health calculator on our platform delivers accurate, research-based results sourced from trusted medical and scientific resources.
Academic Foundation & Data Research
B.Sc. Computer Science from Faculty of Organization & Informatics (FOI), University of Zagreb. His 2013 thesis "DBpedia u primjeni" demonstrated early interest in semantic web data - skills he now applies to organizing and presenting complex health data in an accessible format.
Health Information Research
Works on calculator implementation, data handling, and presenting information in accessible interfaces. Software development experience is not a medical qualification or evidence that a health prediction has been clinically validated.
Our editorial standards emphasize traceable sources, reproducible examples, and clear limitations. A named source alone does not establish the accuracy of every assumption or adjustment in a calculator.
Our Story
What started as a simple idea has grown into a comprehensive health calculation platform
The Beginning
We noticed something frustrating: finding accurate health calculations meant jumping between dozens of sites, each with different formulas and questionable accuracy. Medical professionals had their tools, but regular people were left guessing. We knew we could do better.
The Research
Published formulas, reference data, and research inform parts of the collection. Some tools use approximations that should be understood as educational estimates. We are developers, not clinicians, and we do not claim that every tool has received independent medical review. Our editorial page explains the checks we aim to apply and how readers can report an error.
Today
The collection includes 371 tools across health, fitness, nutrition, and everyday measurements. We welcome reports of unclear explanations, missing sources, or unexpected results through our contact page.
Important Medical Disclaimer
We are developers and health information researchers, not medical professionals. Our calculators are educational tools with varying methods and limitations, not a substitute for a clinical assessment or confirmation of a medication dose.
Always consult qualified healthcare providers for medical advice, diagnosis, or treatment. Never use our calculators as a substitute for professional medical consultation.
Explore More Health Calculators
Discover our complete collection of 371 health calculators