What is BMR (Basal Metabolic Rate)?
Your basal metabolic rate is the minimum number of calories your body burns just to keep you alive if you did nothing but lie down all day. This calculator uses theMifflin-St Jeor formula, which is known to be fairly accurate even without accounting for body fat percentage.
- Male: BMR = 10 Γ weight (kg) + 6.25 Γ height (cm) β 5 Γ age + 5
- Female: BMR = 10 Γ weight (kg) + 6.25 Γ height (cm) β 5 Γ age β 161
What is TDEE (Total Daily Energy Expenditure)?
TDEE is your BMR multiplied by your activity level β the number of calories you need per day to maintain your current weight. Eating less than this amount leads to weight loss; eating more leads to weight gain.
How are the cutting and bulking targets calculated?
Roughly 7,700 kcal is commonly cited as the energy equivalent of 1 kg of body fat, so losing about 0.5 kg a week (roughly 3,850 kcal) works out to eating about 500 kcal less than your TDEE each day. The bulking target is calculated as roughly 300-500 kcal above TDEE, aimed at gaining weight without excess fat.
A note on accuracy
This calculator provides a reference estimate based on widely used formulas (such as Mifflin-St Jeor and Harris-Benedict); your actual basal metabolic rate and calorie needs can differ based on muscle mass, genetics, hormones, and health conditions. If you're pregnant or breastfeeding, have diabetes, thyroid issues, or another underlying condition, or have a history of disordered eating, consult a doctor or registered dietitian rather than relying on this result alone.
Frequently Asked Questions
Is this number completely accurate?
No. It's a formula-based estimate, and actual metabolic rate varies from person to person based on muscle mass, genetics, hormones, and more. The most accurate approach is to track your actual weight change and adjust your calorie intake accordingly.
Is it okay to eat very little?
Extreme calorie restriction can cause muscle loss and a drop in basal metabolic rate. As a general guideline, it's recommended not to go below about 1,200 kcal/day for women or 1,500 kcal/day for men.