Your Basal Metabolic Rate (BMR) is the number of calories your body burns every day just to stay alive — with no movement, no digestion, no exercise. It represents the energy needed for essential functions: keeping your heart beating, your lungs breathing, your cells repairing, and your body temperature regulated.
For most adults, BMR accounts for 60–75% of total daily calorie burn. Even if you did nothing all day, you would still burn this many calories. It's the floor of your calorie needs — and understanding it is the starting point for any nutrition plan.
💡 BMR vs TDEE: BMR is calories at rest. TDEE (Total Daily Energy Expenditure) is your actual daily burn including activity. To manage your weight, you need your TDEE — use our Calorie Calculator to get both at once.
Which BMR Formula Does This Calculator Use?
This calculator uses the Mifflin-St Jeor equation (1990), the most validated formula for modern adult populations:
Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
Compared to the older Harris-Benedict equation (1919), Mifflin-St Jeor is approximately 5% more accurate when validated against indirect calorimetry (the gold standard for measuring actual metabolic rate). The calculator also shows the Harris-Benedict result for comparison.
What Affects Your BMR?
Factor
Effect on BMR
Why
Body weight
Higher weight = higher BMR
More tissue requires more energy to maintain
Muscle mass
More muscle = higher BMR
Muscle tissue burns ~3× more calories at rest than fat
Age
BMR decreases with age
Muscle mass declines ~1-2% per decade after 30
Sex
Men typically 5-10% higher
Men have greater lean mass at same height/weight
Height
Taller = slightly higher BMR
More surface area to maintain temperature
Thyroid function
Can vary BMR by ±30%
Thyroid hormones directly control metabolic rate
How to Use Your BMR to Lose Weight
Your BMR tells you the minimum calories you need to survive. But for weight management, you need your TDEE — your total daily burn including activity. Here's how to use both:
Never eat below your BMR long-term: Consistently eating below BMR triggers metabolic adaptation, muscle breakdown, and hormonal disruption. Your body interprets severe restriction as starvation.
Calculate your TDEE: Multiply your BMR by your activity factor (1.2 for sedentary, 1.55 for moderately active, 1.9 for very active). This is your maintenance calorie level.
Create a moderate deficit: Eat 300–500 calories below your TDEE for sustainable fat loss of 0.3–0.5 kg/week. Use our Calorie Deficit Calculator to find your exact target.
Recalculate regularly: As you lose weight, your BMR decreases (a lighter body burns fewer calories). Recalculate every 4–5 kg lost to keep your target accurate.
BMR by Age and Sex — Reference Table
The values below use the Mifflin-St Jeor formula at average heights and weights for each group:
Profile
Approx BMR
Sedentary TDEE
Moderate TDEE
Woman, 25, 60 kg, 165 cm
~1,385 kcal
~1,660 kcal
~2,150 kcal
Woman, 45, 65 kg, 165 cm
~1,335 kcal
~1,600 kcal
~2,070 kcal
Woman, 65, 62 kg, 163 cm
~1,235 kcal
~1,480 kcal
~1,910 kcal
Man, 25, 80 kg, 178 cm
~1,880 kcal
~2,260 kcal
~2,910 kcal
Man, 45, 85 kg, 178 cm
~1,830 kcal
~2,200 kcal
~2,840 kcal
Man, 65, 78 kg, 175 cm
~1,650 kcal
~1,980 kcal
~2,560 kcal
Frequently Asked Questions
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest to maintain basic life functions — breathing, circulation, cell repair, and temperature regulation. It accounts for 60–75% of total daily calorie burn for most people.
BMR is calories burned at complete rest. TDEE (Total Daily Energy Expenditure) is your total daily calorie burn including activity. TDEE = BMR × activity multiplier. For weight management, TDEE is the more useful number — it tells you how many calories to eat to maintain, lose, or gain weight.
The Mifflin-St Jeor equation (1990) is the most accurate for most adults, validated against indirect calorimetry studies. It is more accurate than the older Harris-Benedict equation (1919) for modern populations. This calculator uses Mifflin-St Jeor as the primary result, with Harris-Benedict shown for comparison.
To lose weight, eat below your TDEE (not your BMR). Eating below your BMR for extended periods causes muscle loss and metabolic adaptation. A healthy deficit is 300–500 calories below TDEE, producing 0.3–0.5 kg of fat loss per week. Use the Calorie Calculator to find your TDEE and set a deficit.
Yes — BMR decreases with age, primarily due to muscle mass loss (sarcopenia). After age 30, BMR declines approximately 1–2% per decade. At age 60, BMR is typically 10–20% lower than at age 20 for the same height and weight. This is why maintaining muscle mass through resistance training becomes increasingly important with age.
Yes — the most effective way to raise BMR is to increase muscle mass through resistance training. Muscle tissue burns approximately 3x more calories at rest than fat tissue. Adding 1–2 kg of muscle can raise BMR by 50–100 calories/day. Eating adequate protein (1.6–2.0 g/kg/day) also supports muscle preservation. There is no credible evidence that "metabolism-boosting" foods, supplements, or detoxes meaningfully raise BMR.
Mifflin MD et al. (1990). A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. doi:10.1093/ajcn/51.2.241
Harris JA, Benedict FG. (1918). A Biometric Study of Human Basal Metabolism. PNAS. doi:10.1073/pnas.4.12.370
Frankenfield D et al. (2005). Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults. J Am Diet Assoc. doi:10.1016/j.jada.2005.05.003
Not a substitute for professional medical or dietary advice. Last updated June 2026.