About Natoras – Free Health Calculators

Our Mission

Natoras was built on one idea: everyone deserves easy access to the same health tools that fitness professionals, dietitians, and clinicians use daily. We offer 30 free calculators covering body composition, nutrition, fitness performance, pregnancy, and general health — all running locally in your browser, with no data collected and no account required.

What We Offer

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Science-Backed Formulas

Every calculation uses validated formulas from published clinical research — Mifflin-St Jeor, Boer, WHO guidelines, and more.

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Private by Default

All calculations run in your browser. We do not store, transmit, or log any personal health data you enter.

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Instant Results

No loading screens, no waiting for a server. Enter your data and get results immediately.

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Works Everywhere

Fully responsive on mobile, tablet, and desktop. No app download needed.

Our Approach to Accuracy

Each calculator is based on a specific, cited methodology. For example:

BMI uses the standard WHO formula: weight (kg) / height² (m²)
Body fat percentage uses the US Navy circumference method
BMR uses the Mifflin-St Jeor equation, the most validated for general populations
Macros follow ISSN and ACSM dietary guidelines for active individuals
Heart rate zones use Tanaka's age-predicted maximum heart rate formula

Where multiple formulas exist, we either use the most widely validated one or present results from several for comparison.

Important Limitations

Natoras calculators are educational tools, not medical devices. Results are estimates based on population averages and may not reflect your individual physiology. Always consult a qualified healthcare professional — your doctor, a registered dietitian, or a certified trainer — before making significant changes to your diet, exercise routine, or health management.

Our pregnancy calculators (due date, ovulation, fertility window) are particularly sensitive — they provide general estimates and are not a substitute for obstetric care.

Who We Are

Natoras is an independent health information project. We are not affiliated with any pharmaceutical company, supplement brand, or healthcare provider. We do not accept paid placements or sponsored content. Our only goal is to give you useful, accurate tools — for free.

Medical Disclaimer: The information and calculators provided on Natoras are for informational and educational purposes only. They do not constitute medical advice and are not a substitute for professional medical consultation, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.