About FitCalcs
FitCalcs is a free collection of 72+ fitness and health tools â calculators, workout generators, reference charts, unit converters, and quizzes â built to give you instant, science-based results without sign-ups, paywalls, or invasive tracking.
The story behind FitCalcs
FitCalcs started with a simple observation: most fitness calculators on the web are surrounded by intrusive ads, pop-ups asking for your email, paywalls, or worst of all, results that have no scientific basis whatsoever. People looking for help with their health goals end up frustrated, confused, or both.
I built FitCalcs as a side project to solve this. Every calculator on this site uses peer-reviewed formulas â Mifflin-St Jeor for calories, US Navy method for body fat, Tanaka for max heart rate, Epley and Brzycki for one-rep max â and the references are documented openly on our methodology page. No black box, no marketing fluff, just the math behind the numbers.
Who is behind FitCalcs?
FitCalcs is built and maintained by a single developer with a long-standing personal interest in fitness, nutrition, and longevity research. I am not a doctor or registered dietitian, which is why every calculator includes a clear health disclaimer and points users to professional consultation for medical decisions.
What I bring to this site is a commitment to using only validated formulas, transparent sourcing, and a strong dislike for the dark patterns that plague the rest of the calculator web. Every tool and article is built to be useful first, monetized second.
Our mission
We believe everyone should have access to accurate health and fitness tools. Whether you're calculating your daily calories, finding your ideal macros, checking your heart rate zones, or estimating your VO2 max â you shouldn't need to create an account or pay for it.
What we offer
Our tools are organized into 8 categories:
- ð Body Composition â 6 tools
- ð Nutrition â 6 tools
- ðŊ Weight Goals â 5 tools
- ðïļ Strength & Lifting â 4 tools
- ð Cardio & Activity â 10 tools
- ð Health & Wellness â 7 tools
- ðĪ° Pregnancy â 2 tools
- ð Supplements & Substances â 3 tools
Plus 8 workout generators, 12 reference charts, 5 fitness quizzes, 4 unit converters, and a growing science-based blog with 20+ articles.
Our approach
- Science-based: Every calculator uses peer-reviewed formulas (Mifflin-St Jeor, US Navy method, Tanaka, Epley, IOM guidelines, etc.). See the full list on our methodology page.
- Privacy-first: All calculations happen in your browser. We never collect, store, or transmit your health data.
- Fast: Static site generation means every page loads in milliseconds. No server processing, no waiting.
- Free: All tools are 100% free with no sign-up required. We sustain the project through non-invasive display advertising.
- Metric + Imperial: Every calculator supports both unit systems.
- Transparent: Read our editorial policy to understand how we research, write, and review content.
How we fund FitCalcs
Running a website costs money â domain, hosting, time. We sustain FitCalcs through non-invasive display advertising (Google AdSense). Advertisers have no influence over our content. We do not accept paid product placements, sponsored articles disguised as editorial, or affiliate-driven recommendations that compromise objectivity.
Important disclaimer
FitCalcs provides estimates based on general population formulas. Our tools are for informational and educational purposes only. They are not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional before making significant changes to your diet, exercise routine, or supplement use, particularly if you have underlying health conditions, are pregnant, or are taking medications.
Get in touch
Spotted an error, have a feature request, or want to give feedback? Visit our contact page. Every message is read and corrections are typically made within 48 hours.
Get started
Browse our full collection of 72+ tools and find what helps you reach your goals.