BMR Calculator — Find Your Basal Metabolic Rate
Discover how many calories your body burns at rest and estimate your daily calorie needs based on activity level.
Your BMR
| Age Group | Male (avg kcal/day) | Female (avg kcal/day) |
|---|---|---|
| 15–19 | 1,750 – 1,850 | 1,400 – 1,500 |
| 20–29 | 1,700 – 1,800 | 1,350 – 1,450 |
| 30–39 | 1,650 – 1,750 | 1,300 – 1,400 |
| 40–49 | 1,600 – 1,700 | 1,250 – 1,350 |
| 50–59 | 1,550 – 1,650 | 1,200 – 1,300 |
| 60+ | 1,450 – 1,550 | 1,150 – 1,250 |
What Is BMR (Basal Metabolic Rate)?
Basal Metabolic Rate (BMR) is the number of calories your body needs to perform its most basic life-sustaining functions while at complete rest. These functions include breathing, blood circulation, cell production, nutrient processing, and maintaining body temperature. BMR accounts for roughly 60–75% of your total daily energy expenditure, making it the single largest component of your calorie burn.
Understanding your BMR is the foundation of any effective weight management strategy. Whether your goal is to lose weight, gain muscle, or simply maintain your current physique, knowing how many calories your body burns at rest helps you plan your nutrition with precision.
How to Calculate BMR
Our free online BMR calculator above uses two of the most scientifically validated equations to estimate your basal metabolic rate:
Mifflin-St Jeor Equation (Recommended)
Developed in 1990, this formula is considered the most accurate for estimating BMR in most adults:
- Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5
- Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161
Harris-Benedict Equation (Revised)
Originally published in 1919 and revised in 1984, this equation is still widely used:
- Men: BMR = 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) − (5.677 × age in years)
- Women: BMR = 447.593 + (9.247 × weight in kg) + (3.098 × height in cm) − (4.330 × age in years)
The American Journal of Clinical Nutrition found the Mifflin-St Jeor equation to be the most reliable predictor of BMR across diverse populations.
BMR vs. TDEE: What Is the Difference?
While BMR measures calories burned at complete rest, your Total Daily Energy Expenditure (TDEE) represents the total number of calories you burn in a day, including physical activity and the thermic effect of food. TDEE is calculated by multiplying your BMR by an activity factor:
- Sedentary (little or no exercise): BMR × 1.2
- Lightly active (light exercise 1–3 days/week): BMR × 1.375
- Moderately active (moderate exercise 3–5 days/week): BMR × 1.55
- Very active (hard exercise 6–7 days/week): BMR × 1.725
- Extra active (very hard exercise or physical job): BMR × 1.9
Our calculator automatically computes your TDEE for all activity levels so you can see the full picture at a glance.
Factors That Affect Your BMR
Several biological and lifestyle factors influence your basal metabolic rate:
- Age: BMR decreases by approximately 1–2% per decade after age 20 due to loss of lean muscle mass.
- Gender: Men typically have a higher BMR than women because they tend to carry more muscle mass and less body fat.
- Body composition: Muscle tissue burns more calories at rest than fat tissue. The more lean muscle you have, the higher your BMR.
- Genetics: Inherited metabolic traits can account for significant variation in BMR between individuals of similar size and age.
- Hormones: Thyroid hormones (T3 and T4) play a major role in regulating metabolism. Conditions like hypothyroidism can lower BMR significantly.
- Climate and body temperature: Exposure to cold environments can temporarily increase BMR as the body works harder to maintain core temperature.
- Diet and nutrition: Severe calorie restriction can lower BMR as the body enters a conservation mode. Learn about balanced nutrition on our Nutrition & Diet page.
How to Use BMR for Weight Management
For Weight Loss
To lose weight, you need to create a calorie deficit — consuming fewer calories than your TDEE. A safe and sustainable deficit is 500–750 calories per day, which translates to approximately 0.5–0.7 kg (1–1.5 lbs) of weight loss per week. Never eat below your BMR for extended periods, as this can slow your metabolism and lead to nutrient deficiencies.
For Weight Gain
To gain weight (particularly lean muscle), aim for a calorie surplus of 250–500 calories above your TDEE, combined with a structured resistance training program. Check our Fitness & Exercise guide for effective workout routines.
For Maintenance
Eating at or near your TDEE will help you maintain your current weight. Regularly recalculating your BMR as your weight, age, or activity level changes ensures your calorie targets stay accurate.
How to Increase Your BMR Naturally
- Build lean muscle: Strength training and resistance exercises increase muscle mass, which raises your resting metabolic rate. Even 2–3 sessions per week can make a noticeable difference.
- Stay active throughout the day: Non-exercise activity thermogenesis (NEAT) — walking, standing, fidgeting — contributes significantly to daily calorie burn.
- Eat enough protein: Protein has a higher thermic effect than carbohydrates or fats, meaning your body burns more calories digesting it. Aim for 1.6–2.2 g of protein per kg of body weight.
- Get quality sleep: Sleep deprivation can reduce BMR and increase hunger hormones. Aim for 7–9 hours per night.
- Stay hydrated: Studies show that drinking 500 ml of water can temporarily boost metabolic rate by 24–30% for about an hour.
- Manage stress: Chronic stress elevates cortisol, which can promote fat storage and reduce metabolic efficiency. Explore natural stress-relief methods on our Home Remedies page.
- Try yoga and mindful movement: Regular yoga practice supports hormonal balance and can positively influence metabolic health.
BMR and Health Conditions
Certain medical conditions can significantly impact your BMR:
- Hypothyroidism: An underactive thyroid slows metabolism, leading to weight gain and fatigue.
- Hyperthyroidism: An overactive thyroid increases BMR, often causing unintended weight loss.
- Polycystic Ovary Syndrome (PCOS): Hormonal imbalances in PCOS can lower BMR and make weight management more challenging.
- Diabetes: Insulin resistance can affect how efficiently the body processes energy.
If you suspect a medical condition is affecting your metabolism, consult a healthcare professional. Learn more about common health conditions on our Diseases & Conditions page. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) offers comprehensive resources on factors affecting weight and metabolism.
BMR Accuracy: What to Keep in Mind
BMR calculators provide estimates based on population-level equations. Individual variation can be 5–10% above or below the calculated value. For the most accurate measurement, indirect calorimetry (a clinical test that measures oxygen consumption and carbon dioxide production) is the gold standard. However, for everyday planning, the Mifflin-St Jeor equation provides a reliable starting point that you can fine-tune based on real-world results.
Frequently Asked Questions About BMR
For adult men, a typical BMR ranges from 1,600 to 1,800 calories per day. For adult women, it usually falls between 1,200 and 1,400 calories per day. These values vary based on age, weight, height, body composition, and genetics.
BMR is a component of your overall metabolism. Your total metabolism includes BMR (calories burned at rest), the thermic effect of food (calories used to digest food), and physical activity. BMR is the largest portion, accounting for about 60–75% of total daily calorie expenditure.
The Mifflin-St Jeor equation is generally considered more accurate for most adults, as confirmed by the American Dietetic Association. The Harris-Benedict equation tends to overestimate BMR by about 5% in some populations. Our calculator supports both so you can compare results.
It is generally not recommended to eat below your BMR for extended periods. Doing so can slow your metabolism, cause muscle loss, and lead to nutritional deficiencies. Instead, create a moderate calorie deficit below your TDEE (not your BMR) for safe and sustainable weight loss.
Yes, regular exercise — especially strength training — can increase your BMR over time by building lean muscle mass. Muscle tissue is metabolically active and burns more calories at rest than fat tissue. High-intensity interval training (HIIT) can also temporarily elevate your metabolic rate for hours after a workout.
BMR naturally declines with age, primarily due to the gradual loss of lean muscle mass (sarcopenia). After age 20, BMR decreases by approximately 1–2% per decade. Staying physically active and maintaining muscle through resistance training can help slow this decline.
BMR (Basal Metabolic Rate) measures the calories your body burns at rest. BMI (Body Mass Index) is a ratio of weight to height used to classify weight status. They measure completely different things — BMR is about energy expenditure, while BMI is about body weight classification. Use our BMI Calculator to check your Body Mass Index.