About HealthFitCalculators

HealthFitCalculators is a free, independent collection of health and fitness calculators built to give you fast, accurate numbers and the context to understand them. Most calculators online hand you a figure with no explanation. We pair every result with plain-language guidance — what the number means, where it falls short, and what a sensible next step looks like — so you leave knowing more than when you arrived.

Who is behind this site

HealthFitCalculators is created and maintained by a small, independent editorial team with backgrounds in fitness coaching, nutrition, and health writing. We are health and fitness enthusiasts and writers, not your doctor: we research each topic from primary sources, but our content is general education rather than personalised medical advice. Where a topic touches clinical territory — such as A1C, pregnancy, or heart rate — we keep our guidance conservative and point you toward a qualified professional.

How we build and check our calculators

Every tool follows the same process:

• Established formulas only. We use well-documented, peer-reviewed equations — Mifflin–St Jeor for metabolic rate, the U.S. Navy circumference method for body fat, the WHO scale for BMI, the Karvonen method for target heart rate, and similar recognised standards. We name the method on each calculator page.
• Manual verification. Before a calculator goes live we test it against worked examples from the source literature to confirm the maths matches.
• Periodic review. We re-check formulas and guidance against current public-health recommendations and update pages as the guidance changes.
• Plain-English context. Every result is paired with what it means, its limitations, and what to do next — never a bare number.

Our editorial standards

We write to inform, not to sell. Our guidance is based on mainstream, evidence-based health and fitness science; we avoid fad claims and miracle fixes. When we mention a product or link to an external resource we say so clearly, and any commercial link is labelled. Found something wrong or out of date? Tell us — we correct errors quickly and genuinely value the feedback.

Privacy by design

Every calculation runs entirely in your browser. The height, weight, and other figures you enter are never sent to a server, never stored, and never linked to you. We don't ask you to register, and the tools are free to use. See our Privacy Policy for the full detail.

What we offer

• BMI Calculator — body mass index with the full WHO category scale.
• BMR Calculator — the calories your body burns at complete rest.
• Calorie Calculator — daily energy needs (TDEE) plus goal targets.
• Body Fat Calculator — the U.S. Navy circumference method.
• Ideal Weight Calculator — four classic clinical formulas.
• Macro Calculator — protein, carbs and fat from your calorie target.

… plus more than twenty other tools covering body composition, energy needs, training, heart health, and pregnancy. Browse them all on the homepage.

An important note

These calculators are educational tools that estimate population-level averages. They are not a substitute for professional medical advice, diagnosis, or treatment. Always talk to a qualified healthcare provider before making significant changes to your diet, exercise, or health routine. See our Terms & Medical Disclaimer for details.

Get in touch

Questions, corrections, or suggestions for a calculator we should add? Visit our contact page — we read everything.