Calculate your Basal Metabolic Rate to determine how many calories your body burns at rest and estimate your Total Daily Energy Expenditure
Enter your details and click calculate to see your Basal Metabolic Rate and Total Daily Energy Expenditure
Basal Metabolic Rate (BMR) represents the number of calories your body burns at complete rest to maintain essential physiological functions. This includes breathing, circulation, cell production, nutrient processing, and maintaining body temperature. Your BMR accounts for approximately 60-75% of your total daily calorie expenditure, making it the largest component of your energy budget.
Understanding your BMR provides the foundation for calculating your Total Daily Energy Expenditure (TDEE), which includes calories burned through physical activity and digestion. This information is crucial for setting appropriate calorie targets whether your goal is weight loss, muscle gain, or maintenance. Without knowing your BMR and TDEE, any diet plan is essentially guesswork.
This calculator uses the Mifflin-St Jeor equation, considered the most accurate formula for estimating BMR in the general population. The formula differs slightly for men and women to account for differences in typical body composition and metabolic rates.
For Men: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5
For Women: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161
The equation accounts for the fact that muscle tissue burns more calories than fat tissue, men typically have more muscle mass than women, and metabolic rate naturally declines with age as muscle mass decreases.
Your BMR represents calories burned at complete rest, but you burn additional calories through daily activities, exercise, and digestion. To calculate Total Daily Energy Expenditure (TDEE), your BMR is multiplied by an activity factor that reflects your typical daily activity level.
| Activity Level | Multiplier | Description |
|---|---|---|
| Sedentary | BMR × 1.2 | Little or no exercise, desk job, minimal daily movement |
| Lightly Active | BMR × 1.375 | Light exercise or sports 1-3 days per week |
| Moderately Active | BMR × 1.55 | Moderate exercise or sports 3-5 days per week |
| Very Active | BMR × 1.725 | Hard exercise or sports 6-7 days per week |
| Extremely Active | BMR × 1.9 | Very hard exercise daily, physical job, training twice per day |
Once you know your BMR and TDEE, you can set appropriate calorie targets based on your specific goals. The fundamental principle of energy balance remains constant: calories consumed versus calories expended determines whether you gain, lose, or maintain weight.
To lose weight, you must consume fewer calories than your TDEE, creating a caloric deficit. A moderate deficit of 300-500 calories below TDEE typically produces sustainable fat loss of 0.5-1 kg (1-2 pounds) per week without excessive hunger or muscle loss. More aggressive deficits (750-1000 calories) can work for obese individuals but become increasingly difficult to maintain and may cause muscle loss.
Building muscle requires a caloric surplus to provide energy and raw materials for muscle protein synthesis. A modest surplus of 200-400 calories above TDEE supports muscle growth while minimizing fat gain. Larger surpluses don't accelerate muscle building proportionally—muscle synthesis has biological rate limits—but do increase fat accumulation.
To maintain your current weight, consume calories approximately equal to your TDEE. This represents the equilibrium point where energy intake matches energy expenditure. Maintenance calories are useful during diet breaks, when transitioning between cutting and bulking phases, or when satisfied with current body composition.
Note that maintenance calories aren't perfectly static—they fluctuate based on daily activity variations, stress levels, sleep quality, and hormonal factors. Aim for your calculated TDEE on average, understanding that some days you'll eat slightly more or less while still maintaining weight over time.
Use your calculated TDEE as a starting point, but verify it against real-world results. Track your weight weekly (same day, same time, same conditions) and food intake for 2-3 weeks. If weight doesn't change as expected, adjust calories by 100-200 and reassess.
During prolonged caloric deficits, your metabolism adapts by reducing NEAT (non-exercise activity thermogenesis) and becoming more efficient. After 8-12 weeks of dieting, take a 1-2 week diet break at maintenance calories to restore metabolic function.
Non-exercise activity thermogenesis (daily movement outside formal exercise) can vary by 500+ calories between individuals. Increase NEAT through walking, taking stairs, standing desks, and general movement to increase TDEE without formal exercise.
Recalculate your BMR annually, especially after age 30 when metabolic decline accelerates. Maintaining muscle mass through resistance training is the most effective way to prevent age-related BMR decreases.
Standard BMR equations don't directly account for body composition. Muscular individuals may have higher actual BMRs than calculated, while those with higher body fat may have lower actual BMRs. Use calculations as starting estimates, then adjust based on results.
Most people significantly overestimate their activity level. A gym session doesn't make you "Very Active" if you sit at a desk the rest of the day. Choose the activity level that accurately reflects your entire typical day, not just your workout time.
BMR is a component of your total metabolism but not the entirety of it. Your metabolism encompasses all energy-requiring processes in your body, including BMR (resting energy expenditure), physical activity, the thermic effect of food (calories burned digesting food), and NEAT (non-exercise movement). BMR specifically refers only to the calories required for basic physiological functions at complete rest.
Yes, but options are limited. Building muscle mass is the most effective way to increase BMR since muscle tissue burns more calories at rest than fat tissue. Resistance training 3-4 times weekly can gradually increase BMR over months and years. Eating adequate protein also slightly increases metabolic rate through its higher thermic effect. However, most metabolic "boosters" marketed online have minimal impact—the best strategy is building and maintaining muscle mass.
BMR declines with age primarily due to sarcopenia—the natural loss of muscle mass that occurs without resistance training. Most people lose 3-8% of muscle mass per decade after age 30, reducing metabolically active tissue. Hormonal changes (decreased growth hormone, testosterone, and thyroid function) also contribute. However, this decline is not inevitable—regular strength training and adequate protein intake substantially slow or prevent age-related BMR decreases.
You should base your calorie intake on your TDEE, not your BMR. Your TDEE includes all calories you burn daily (BMR plus activity), making it the relevant number for setting intake targets. Eating at your BMR would create an excessive deficit for most people since BMR doesn't include activity calories. For weight loss, eat 300-500 calories below TDEE. For muscle gain, eat 200-400 above TDEE. For maintenance, eat approximately at TDEE.
BMR calculators using the Mifflin-St Jeor equation are accurate within 10-15% for most people. However, individual variation exists due to genetic factors, body composition differences, and metabolic health. The calculations provide useful estimates but shouldn't be treated as absolute values. Use the calculated BMR as a starting point, then adjust based on real-world results after tracking for 2-4 weeks.
Prolonged severe caloric restriction (below 1000-1200 calories for extended periods) does cause metabolic adaptation where your body becomes more efficient and BMR decreases beyond what's expected from weight loss alone. However, this "metabolic damage" is largely reversible with gradual refeeding and isn't permanent. The bigger concern is muscle loss during aggressive dieting, which permanently reduces BMR. Moderate caloric deficits (20-25% below TDEE) minimize adaptation while still producing fat loss.