About HealthCalculators

HealthCalculators exists to make everyday health numbers understandable, free, and private. We believe everyone should be able to calculate a BMI, estimate daily calories, or track a pregnancy milestone without signing up, paying a fee, or surrendering personal data to an advertising network.

Every calculator on this site is built on publicly available formulas from recognized organizations including the World Health Organization (WHO), the U.S. CDC, and the U.S. National Institutes of Health (NIH). We do not invent our own formulas. We translate established reference equations into clear, fast, browser-based tools that return a number, a visual chart, and a plain-English explanation in under a minute.

Our mission is educational. We want to help you understand what a number means, where it comes from, and what its limits are — not to replace a conversation with a qualified professional. A BMI of 26 is not a verdict; it is a starting point for understanding your body composition. A TDEE estimate is not a rule; it is a reference for thinking about energy balance.

We publish every formula source, mark calculators with enhanced disclaimers where multiple valid formulas exist, and process every calculation locally in your browser. Privacy is not a feature tier here. It is the default.

HealthCalculators holds itself to three standards: transparency, honesty about limits, and privacy by default.

Transparency. Every calculator page names the formula it uses and links to its source. BMI uses the WHO reference equation. BMR defaults to Mifflin-St Jeor, published in 1990, with Harris-Benedict available for cross-reference. Body fat offers both the Navy circumference method and the YMCA two-input method side by side. Ideal weight shows Devine, Hamwi, and Robinson together. We never hide which equation produced your number.

Honesty about limits. A formula is a model, not a measurement. BMI cannot distinguish muscle from adipose tissue. BMR is a regression estimate with a confidence interval. Body fat from circumference equations carries a four-to-five percentage point error band. Calculators that more directly inform personal decisions, such as calorie targets and pregnancy dates, carry an enhanced disclaimer reminding you that the number is a starting point, not a verdict, and not a substitute for guidance from a qualified professional.

Privacy by default. Every calculation runs locally in your browser. We do not send your inputs to a server. The only exception is the optional AI Insight feature, which sends only the computed result values to our API route to generate a plain-English explanation. We never store that data.