Health
BMR Calculator
Discover the calories your body burns at rest.
What Is BMR and Why Does It Matter?
Your Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest — just to keep your heart beating, lungs breathing, and organs functioning. It accounts for roughly 60–70% of total daily calorie expenditure for most people.
Understanding your BMR is the foundation of any nutrition plan. Eating significantly below your BMR for extended periods leads to muscle loss and metabolic slowdown. Eating at or slightly above TDEE (Total Daily Energy Expenditure) is the basis for healthy weight management.
BMR Formulas Explained
- Mifflin-St Jeor (most accurate): Men: (10 × kg) + (6.25 × cm) − (5 × age) + 5. Women: same − 161
- Harris-Benedict (original, 1919): older formula, slightly less accurate for modern populations
- Katch-McArdle: uses lean body mass — most accurate if you know your body fat %
Activity Multipliers (TDEE)
- Sedentary (desk job, no exercise): BMR × 1.2
- Lightly active (1–3 days/week): BMR × 1.375
- Moderately active (3–5 days/week): BMR × 1.55
- Very active (6–7 days/week): BMR × 1.725
- Extra active (athlete/physical job): BMR × 1.9
How many calories should I eat to lose weight?
A deficit of 500 calories/day below your TDEE leads to approximately 1 lb (0.45 kg) of fat loss per week. Never eat below your BMR for extended periods as it causes muscle loss and hormonal disruption. A moderate deficit of 15–20% below TDEE is sustainable for most people.
Does muscle increase BMR?
Yes. Muscle tissue burns approximately 6 calories per pound per day at rest, compared to fat tissue which burns only 2 calories per pound. Building muscle through resistance training is one of the most effective ways to increase your resting metabolic rate long-term.