Overview
How it's calculated
Enter your stats and activity level. Mifflin-St Jeor is the modern default; Harris-Benedict is the classic; Katch-McArdle uses your body-fat % (most accurate if you know it). Your BMR is multiplied by an activity factor from 1.2 (sedentary) to 1.9 (very active).
Mifflin-St Jeor: BMR = 10×kg + 6.25×cm − 5×age + (male +5 / female −161) TDEE = BMR × activity factor
How to read your result
Maintenance is a starting estimate, not a fixed truth — track weight for 2–3 weeks and adjust. The result also shows a ~500 kcal deficit (mild fat loss) and a ~300 kcal surplus (lean gain). Feed your target into the macro calculator to split it.
Frequently asked questions
BMR vs TDEE — what's the difference?
BMR is what you burn at complete rest. TDEE is BMR plus activity, digestion and movement — your real daily maintenance calories.
Which formula should I pick?
Mifflin-St Jeor for most people. Use Katch-McArdle if you have a reliable body-fat measurement, since it accounts for lean mass.
Why isn't my weight matching the estimate?
Formulas are population averages. Use the number as a starting point, then nudge calories based on 2–3 weeks of real scale data.
Sources & references
- Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247.
- Harris JA, Benedict FG. A biometric study of human basal metabolism. Proc Natl Acad Sci. 1918;4(12):370-373.
- Katch FI, McArdle WD. Nutrition, Weight Control, and Exercise. Lea & Febiger; 1977.
Medical disclaimer
This calculator is for general educational purposes only and is not medical advice. Estimates are based on population formulas and may not fit your individual situation. Consult a qualified healthcare or fitness professional before making health, nutrition or training decisions.