Formulas we use
- Mifflin-St Jeor (1990) — the default BMR equation. Found to be the most accurate predictive equation for healthy adults in a 2005 review by the American Dietetic Association.
- Katch-McArdle — used when you enter body fat %, since it accounts for lean body mass.
- Revised Harris-Benedict (1984) — shown for comparison on the BMR calculator.
- Activity multipliers — 1.2 to 1.9, the standard factors used in sports nutrition.
- Energy density of fat — about 7,700 kcal per kg (3,500 per lb), used for deficit planning.
Limitations
Every formula is an estimate. Individual metabolism can differ by ±10% or more. Use the numbers as a starting point, track your weight for 2–3 weeks, and adjust. These tools are for healthy adults and are not medical advice — if you're pregnant, have a medical condition or a history of eating disorders, talk to a doctor or registered dietitian.
Privacy
All calculations happen in your browser. We don't store the numbers you enter.