BMR
CALCULATOR
Find the calories your body burns at complete rest — the foundation of all nutrition planning.
What This Calculator Does
The BMR Calculator computes your Basal Metabolic Rate — the calories your body burns at complete rest to maintain vital functions. It shows both Mifflin-St Jeor (most accurate) and Harris-Benedict results, plus activity-adjusted TDEE estimates.
The Formula Explained
Mifflin-St Jeor (men): BMR = (10 × kg) + (6.25 × cm) − (5 × age) + 5. Mifflin-St Jeor (women): same but −161. Example: 30-year-old female, 165cm, 65kg → BMR = (650 + 1,031 − 150 − 161) = 1,370 kcal/day at complete rest.
What Your Result Means
BMR represents 60–70% of your TDEE. Muscle mass is the primary driver of BMR — each kg of lean muscle burns ~13 kcal/day at rest. This is why resistance training permanently raises your metabolism. Your BMR decreases roughly 1–2% per decade after 30 unless you actively preserve muscle.
TDEE Calculator to add your activity level · Calorie Calculator for goal-specific targets
What Is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to maintain basic physiological functions: breathing, circulation, cell production, and body temperature regulation. BMR typically represents 60 to 70 percent of total daily calorie expenditure and is the foundational number behind all nutrition and energy calculations.
Mifflin-St Jeor vs Harris-Benedict
The Mifflin-St Jeor equation (1990) is the most accurate formula for most people and is recommended by the American Dietetic Association. It outperforms the older Harris-Benedict equation (1919) by approximately 5% in studies comparing predicted vs measured metabolic rate. However, neither formula accounts for lean body mass, which is why the Katch-McArdle formula (using body fat percentage) is more accurate for very lean or very muscular individuals.
BMR vs TDEE
BMR is your resting calorie burn. TDEE (Total Daily Energy Expenditure) is BMR multiplied by an activity factor — your real-world daily calorie burn. Multiply your BMR by 1.2 for sedentary, 1.375 for lightly active, 1.55 for moderately active, 1.725 for very active, and 1.9 for extremely active individuals.