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Use this free BMR Calculator to accurately calculate your Basal Metabolic Rate (BMR) — the precise number of calories your body burns at rest to sustain essential vital physiological functions including breathing, blood circulation, cell regeneration, brain function, and hormonal regulation. This online BMR calculator uses the gold-standard Mifflin–St Jeor equation — the most clinically validated and widely recommended BMR formula by registered dietitians and nutritionists — alongside the classic Harris-Benedict BMR formula for cross-reference. Simply enter your age, gender, height, and weight to get your BMR in calories per day, then apply your Physical Activity Level (PAL) multiplier to calculate your full Total Daily Energy Expenditure (TDEE) across activity levels: Sedentary · Lightly Active · Moderately Active · Very Active · Extra Active.
Your BMR and TDEE results form the essential nutritional baseline for calculating an accurate daily calorie target tailored to your specific goal — whether that's a calorie deficit for weight loss, calorie maintenance for weight management, or a calorie surplus for muscle gain and bulking. Combined with macronutrient tracking (protein, carbohydrates, and fats), your BMR calculation becomes the foundation of any effective diet plan, meal prep strategy, or body recomposition program — used by personal trainers, sports nutritionists, and fitness coaches worldwide to design evidence-based nutrition and calorie intake plans.
⚠ Medical Disclaimer: This BMR calculator provides a scientifically based calorie estimate for informational and educational purposes only. Individual metabolic rates vary based on genetics, thyroid function, lean muscle mass, medications, and underlying health conditions. These results should not replace advice from a licensed doctor, registered dietitian (RD), or certified nutritionist. Always consult a qualified healthcare professional before making significant changes to your diet or calorie intake.
Basal Metabolic Rate (BMR) represents the number of calories your body needs to maintain essential life functions while at complete rest. These functions include breathing, circulation, cell production, nutrient processing, and maintaining body temperature.
A BMR calculator estimates how many calories your body burns in a 24-hour period without any physical activity. This value is an important starting point for understanding metabolism, calorie requirements, weight management, and overall energy expenditure.
Knowing your basal metabolic rate allows you to determine how many calories you need each day for different goals such asweight loss, muscle gain, or weight maintenance.
Health professionals, nutritionists, and fitness experts frequently useBMR calculations to design diet plans and evaluate metabolic health.
The Mifflin–St Jeor equation is widely considered one of the most accurate formulas for estimating basal metabolic rate in healthy adults. It uses body weight, height, age, and biological sex to estimate the calories your body burns at rest.
For Men:
For Women:
Where:
This formula estimates the minimum calories required for survivalif the body were completely at rest for an entire day.
While BMR represents calories burned at rest,Total Daily Energy Expenditure (TDEE) accounts for additional calories burned through physical activity and lifestyle movement.
To estimate total daily calorie requirements, BMR is multiplied by anactivity factor that reflects how active a person is.
| Activity Level | Multiplier | Description |
|---|---|---|
| Sedentary | 1.2 | Little or no exercise |
| Lightly Active | 1.375 | Light exercise 1-3 days per week |
| Moderately Active | 1.55 | Moderate exercise 3-5 days per week |
| Very Active | 1.725 | Hard exercise 6-7 days per week |
| Extremely Active | 1.9 | Athletes or physically demanding jobs |
Using this method allows you to estimate the number of calories required to maintain body weight based on your lifestyle.
Several biological and lifestyle factors influencebasal metabolic rate. Understanding these factors can help explain why calorie requirements vary between individuals.
Because these factors vary, two individuals with similar body weights may still have different BMR values.
Understanding your basal metabolic rate is essential for creating effective diet and fitness strategies.
Once BMR is calculated, you can determine how many calories to consume based on specific goals.
| Goal | Calorie Strategy |
|---|---|
| Weight Maintenance | Consume calories close to your TDEE |
| Weight Loss | Create a calorie deficit of 300-500 calories daily |
| Muscle Gain | Consume a calorie surplus combined with strength training |
Using a BMR calculator provides a foundation for understanding how your body uses energy and how nutrition and exercise can influence metabolism.
Health Disclaimer: BMR calculations provide estimates only and should not replace professional medical or nutritional advice.
Basal Metabolic Rate (BMR) represents the number of calories your body needs to perform basic life-sustaining functions such as breathing, blood circulation, and cell production while at complete rest.
BMR is calculated using formulas that consider age, height, weight, and biological sex. One of the most commonly used equations is the Mifflin–St Jeor formula.
This calculator uses the Mifflin–St Jeor equation, which is widely regarded as one of the most accurate formulas for estimating basal metabolic rate in adults.
Knowing your BMR helps determine how many calories your body burns at rest. This information can help you plan calorie intake for weight loss, weight maintenance, or muscle gain.
No. BMR represents calories burned at rest. Your daily calorie needs depend on activity level, exercise, and lifestyle factors.
BMR measures calories burned at rest, while Total Daily Energy Expenditure (TDEE) includes calories burned through physical activity and daily movement.
Anyone interested in managing body weight, improving fitness, or understanding metabolism can benefit from using a BMR calculator.
Yes. BMR generally decreases with age because muscle mass tends to decline and metabolism slows down over time.
Yes. Muscle tissue burns more calories than fat tissue, so individuals with more muscle mass typically have higher BMR values.
Men typically have more lean muscle mass and lower body fat percentages, which increases metabolic rate.
Yes. BMR changes with age, body composition, weight changes, and lifestyle habits.
Key factors include genetics, age, body composition, hormone levels, physical activity, and overall health.
Increasing muscle mass through strength training, improving nutrition, and maintaining an active lifestyle can help boost metabolic rate.
Regular exercise can indirectly increase BMR by building muscle mass and improving metabolic efficiency.
No. BMR varies from person to person depending on body composition, age, genetics, and lifestyle.
The Mifflin–St Jeor equation estimates basal metabolic rate based on weight, height, age, and biological sex.
BMR calculators provide estimates based on established metabolic formulas, but actual metabolism can vary among individuals.
Most adults burn between 1,200 and 2,000 calories per day at rest, depending on body size and metabolism.
Yes. Understanding BMR allows you to calculate calorie deficits needed for sustainable fat loss.
Consuming fewer calories than your BMR is generally not recommended because it may slow metabolism and reduce energy levels.
Resting metabolic rate is similar to BMR but measured under less strict conditions. It represents calories burned at rest during normal daily conditions.
Proper hydration can support metabolic processes and overall body function.
Yes. This BMR calculator is completely free and works instantly in your browser.
No. All calculations happen locally in your browser and no personal data is stored.
Using an online BMR calculator is the easiest way to estimate basal metabolic rate by entering basic personal data.