Health Calculators
Evidence-based tools for body composition, nutrition, and wellness. Every calculation uses clinically validated formulas — WHO, Mifflin-St Jeor, US Navy, and Naegele's rule.
Calculate your Body Mass Index in metric or imperial. Shows your healthy weight range and WHO category.
Calculate →Basal Metabolic Rate — the calories your body burns at complete rest. Foundation of any diet or training plan.
Calculate →Find your TDEE and daily calorie target for weight loss, muscle gain, or maintenance using Mifflin-St Jeor.
Calculate →Estimate body fat percentage using the US Navy circumference method. Shows fat mass and lean mass.
Calculate →Find your exact age in years, months, and days. Also shows total days lived and days until your next birthday.
Calculate →Pregnancy due date from your last menstrual period. Shows conception date, trimester milestones, and current week.
Calculate →About These Calculators
Every health calculator on ZedCalculator uses published clinical formulas. Here's what powers each one:
- BMI — WHO formula: weight (kg) ÷ height (m)². Categories follow WHO international standards.
- BMR / Calorie — Mifflin-St Jeor equation, published 1990. Considered the most accurate for the general population.
- Body Fat — US Navy circumference method, developed by Hodgdon & Beckett (1984). Error margin ±3–4%.
- Due Date — Naegele's rule: LMP + 280 days. The obstetric standard worldwide.
Important Disclaimer
These tools provide estimates based on population averages. They are for informational purposes only and are not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for medical decisions.