calculatory.app

Health Calculators (4 tools)

Free US health and body composition calculators. CDC-aligned BMI categories, the Mifflin-St Jeor calorie formula used by US dietitians, the US Navy body fat tape method, and ACOG pregnancy dating. No signup, no tracking — calculations run entirely in your browser.

All health calculators

BMI

Body Mass Index with CDC categories and healthy weight range for your height in feet/inches and pounds.

PopularEssential

Calorie / TDEE

Daily calorie needs using the Mifflin-St Jeor equation, adjusted for activity level and goal.

Popular

Body Fat

Estimate body fat percentage using the U.S. Navy method or BMI-based approximation.

Due Date

Pregnancy due date and full timeline of milestones based on last menstrual period.

About these calculators

These tools use established US clinical standards. BMI categories follow the 1998 CDC/WHO classification still in use today. The calorie calculator uses the Mifflin-St Jeor equation (1990), considered the most accurate predictive formula by the Academy of Nutrition and Dietetics. Body fat uses the US Navy circumference method (1984), the same protocol the US military uses for body composition standards. Pregnancy dating follows Naegele's rule and the American College of Obstetricians and Gynecologists (ACOG) term definitions.

All measurements support both US imperial (pounds, feet/inches) and metric (kilograms, centimeters). Each calculation runs in your browser — nothing is sent to a server.

These calculators are estimates and screening tools, not medical advice. For pregnancy care, nutrition with underlying conditions, or weight-related health concerns, work with a qualified clinician.

Which calculator should I use?

  • Quick body-weight check: BMI Calculator — fastest screening for most adults
  • Body composition (more than just weight): Body Fat Calculator — better for muscular individuals where BMI is misleading
  • Diet planning: Calorie / TDEE Calculator — gives daily target plus macro breakdown
  • Pregnant or planning: Due Date Calculator — full prenatal timeline with key milestones