Free Health Calculators

Evidence-based health math with instant results — BMI, daily calorie needs and more. Live as you type, private by design, no signup ever.

About Our Health Calculators

ToolsFlash health calculators use formulas published in peer-reviewed research — the WHO BMI classification and the Mifflin-St Jeor equation for calorie needs, widely regarded as the most accurate for the general population. All calculations run in your browser: your height, weight and personal details are never sent to a server.

Which calculator do I need?

  • BMI Calculator — check whether your weight falls in the underweight, healthy, overweight or obese range, and see your personal healthy weight window. Supports metric and imperial units.
  • Calorie Calculator — find your BMR (calories burned at rest) and TDEE (total daily burn), plus practical calorie targets for losing, maintaining or gaining weight.

Note: these tools are for general information only and are not a substitute for professional medical advice.