How Your Calorie Needs Are Calculated
This calculator uses the Mifflin-St Jeor equation, shown in clinical studies to be the most accurate BMR formula for the general population:
Men: BMR = 10×weight(kg) + 6.25×height(cm) − 5×age + 5
Women: BMR = 10×weight(kg) + 6.25×height(cm) − 5×age − 161
Your TDEE multiplies BMR by an activity factor (1.2 sedentary → 1.9 extremely active). Eating at TDEE maintains your weight; a ~500 kcal daily deficit loses about 0.5 kg per week; a ~500 kcal surplus gains about the same.
Using Your Numbers Wisely
- Start with maintenance for 1–2 weeks and confirm your weight is stable — individual metabolisms vary ±10%.
- Prefer moderate deficits — aggressive cuts lose muscle, tank energy and rarely last.
- Don't eat below BMR for extended periods without medical supervision.
- Re-calculate as you go — needs change as your weight changes. Check your BMI alongside.
This tool provides general estimates and is not medical advice. Consult a professional for personalized nutrition guidance.
Frequently Asked Questions
How many calories should I eat per day?
Calculate your TDEE, then eat roughly that amount to maintain, ~500 kcal less to lose ~0.5 kg/week, or 300–500 kcal more to gain steadily.
What is BMR?
Basal Metabolic Rate — calories burned at complete rest to keep you alive. This tool uses the Mifflin-St Jeor equation, the most accurate for the general population.
What is TDEE?
Total Daily Energy Expenditure — BMR × activity factor (1.2–1.9). It estimates the total calories you burn each day including exercise.
How big should a calorie deficit be?
About 500 kcal/day for ~0.5 kg (1 lb) of loss per week — safe and sustainable. Avoid prolonged eating below your BMR without medical supervision.