About our health calculators
Each health calculator uses formulas published in peer-reviewed research and used by clinicians and dietitians — for example the Mifflin-St Jeor equation for metabolic rate, the U.S. Navy method for body fat and Naegele's rule for due dates. We explain the formula, its limits and how to read your result on every page.
Use results as a starting point
Population formulas describe averages. Your genetics, muscle mass, medications and medical history all matter, so treat any single number as a helpful estimate and track trends over time rather than day-to-day changes. If a result surprises you, talk to a healthcare professional.