Basal metabolic rate
How much energy does your body burn at rest? Enter your stats and find out.
Your BMR
1,649kcal / day
BMR (basal metabolic rate) is what your body burns at complete rest. It's calculated using the Mifflin-St Jeor equation. Add activity on top to get daily needs — estimates are a starting point, not a prescription.
Basal metabolic rate (BMR) is the minimum number of calories your body expends daily at complete rest, with no physical activity. It accounts for roughly 60–75% of total daily energy expenditure in sedentary people and represents the energy cost of maintaining core functions: brain activity, heartbeat, respiration, protein synthesis, and cellular processes. Your BMR is unique to your body composition, age, and genetics.
The calculator applies the Mifflin-St Jeor equation, a clinically validated formula developed in 1990 that outperforms older Harris-Benedict estimates. It factors your sex (men have higher BMR due to greater lean muscle), age (BMR drops ~2% per decade after 20), body weight, and height. After calculating BMR, multiplying by your activity factor (sedentary, lightly active, moderately active, very active, or extremely active) gives your total daily energy expenditure (TDEE), showing how many calories you actually burn with exercise included.
Men: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5 | Women: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161Weight, height, and age feed into a linear equation calibrated against indirect calorimetry studies. The constants (10, 6.25, 5) represent coefficients for metabolic contribution of muscle, bone, and organ tissue; the sex-specific offsets (+5 for men, −161 for women) correct for hormonal and body-composition differences.
| Input | Result | Notes |
|---|---|---|
| 25-year-old male, 180 cm (5'11"), 75 kg (165 lbs) | BMR = 1,751 calories/day | A young, lean man with solid muscle. At sedentary activity level, his TDEE ≈ 2,101 cal/day; at moderate exercise, ≈ 2,756 cal/day. |
| 40-year-old female, 165 cm (5'5"), 65 kg (143 lbs) | BMR = 1,378 calories/day | A middle-aged woman. At sedentary level, TDEE ≈ 1,654 cal/day; with 3–4 days/week exercise, ≈ 2,158 cal/day. |
| 55-year-old male, 172 cm (5'8"), 82 kg (180 lbs) | BMR = 1,672 calories/day | Older adult, heavier build. Age and weight both matter; TDEE at moderate activity ≈ 2,487 cal/day. Strength training helps preserve BMR. |
No. BMR (basal metabolic rate) is measured under strict conditions—fasting, awake, complete rest, in a thermally neutral environment. RMR (resting metabolic rate) is measured after 12–24 hours of rest and is ~10% higher in real life. Both use the Mifflin-St Jeor formula and are often used interchangeably in fitness contexts.
BMR is sensitive to lean body mass (muscle, organs, bone), not just weight. If your friend has more muscle or bone density, their BMR will be higher. Age also matters—a 20-year-old and 50-year-old at the same weight and height will differ by ~100–150 cal/day. Hormones, genetics, and medical conditions also play a role.
Very low deficits (< 20% below BMR) for short periods can work, but sustained intake below BMR triggers metabolic slowdown, muscle loss, and nutrient deficiency. A moderate deficit of 300–500 cal/day below your TDEE is safer and more sustainable—expect ~0.25–0.5 kg loss per week.
One kilogram of muscle burns roughly 50–100 cal/day at rest (estimates vary). Gaining 2 kg of lean muscle over a year raises BMR by ~100–200 cal/day. This is one reason strength training is effective for long-term weight management—it compounds your baseline burn.
Yes. Intense resistance training and building muscle raises BMR. Prolonged calorie restriction (especially below BMR) lowers it by 10–25%, a protective adaptation called metabolic adaptation. Refeeding and returning to TDEE typically restores BMR over 2–4 weeks.
Always use TDEE—it includes your activity level. BMR alone ignores exercise; using only BMR grossly underestimates your actual calorie burn and leads to unintended rapid weight loss or muscle loss. Think of BMR as the foundation; TDEE is your real-world budget.