BMR & TDEE Calculator
Find your Basal Metabolic Rate and Total Daily Energy Expenditure, then get a personalized calorie and macro target for your fitness goal.
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BMR vs TDEE: the difference matters
BMR (Basal Metabolic Rate) is what you'd burn lying still in bed all day. TDEE (Total Daily Energy Expenditure) is BMR plus your actual activity — walking, training, even digesting food. Use TDEE for weight management, not BMR. Eating at BMR for weeks would cause weight loss because BMR doesn't include daily movement.
Why Mifflin-St Jeor?
The Mifflin-St Jeor equation (1990) replaced the older Harris-Benedict equation as the clinical standard. It's accurate to within 10% for most people, including those who are obese or elderly. It uses four variables: sex, weight (kg), height (cm), and age (years). For men: 10×kg + 6.25×cm − 5×age + 5. For women: 10×kg + 6.25×cm − 5×age − 161.
How to use this for fat loss or muscle gain
For fat loss, target a 300-500 calorie daily deficit. You'll lose roughly 0.5 kg (1 lb) of fat per week. For muscle gain, a 200-300 calorie surplus is enough — bigger surpluses convert to fat, not muscle. Recalculate your TDEE every 4-6 weeks as your weight changes, since lighter bodies need fewer calories and heavier bodies need more.
Frequently asked questions
What is BMR?
BMR (Basal Metabolic Rate) is the calories your body burns at complete rest to maintain basic functions: breathing, circulation, cell production, and brain activity. It accounts for 60-70% of daily calorie burn for most people.
What is TDEE?
TDEE (Total Daily Energy Expenditure) is your BMR plus all calories burned through activity. Eat below TDEE to lose weight, above to gain, at TDEE to maintain.
How accurate is the Mifflin-St Jeor equation?
Mifflin-St Jeor is the most accurate BMR formula for most people, about 80-90% accurate vs lab measurements. It outperforms Harris-Benedict, especially for obese and older individuals.
Should I eat below my TDEE to lose weight?
Yes, but moderately. A 300-500 cal/day deficit is sustainable. Larger deficits cause muscle loss and metabolic slowdown. Avoid going below 1200 cal (women) or 1500 cal (men) without medical supervision.
How are macros calculated?
Protein at 1.8 g/kg (cut) or 1.6 g/kg (maintain/bulk). Fat at 25% of calories. Carbs fill the remainder. Adjust based on training intensity and personal preference.