Find out how many calories your body needs at rest with our accurate BMR calculator. Understand your metabolism better to optimize weight loss, maintenance, or muscle gain plans.
What is BMR?
BMR (Basal Metabolic Rate) represents the number of calories your body burns every day to maintain basic physiological functions like breathing, blood circulation, and cell production — while at complete rest.
It accounts for the minimum energy your body needs just to keep you alive.
Knowing your BMR helps you understand your metabolism and plan your diet and exercise routine effectively.
Why is BMR Important?
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It’s the foundation of your daily calorie needs.
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Helps you figure out how much energy you burn without exercise.
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Guides your calorie intake for weight loss, maintenance, or muscle gain.
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Useful for athletes, fitness enthusiasts, and anyone tracking their health.
How is BMR Calculated?
There are several formulas to calculate BMR, but the most widely accepted and accurate ones are:
1. Mifflin-St Jeor Equation (most accurate for modern populations)
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For men:
BMR = 10 × weight (kg) + 6.25 × height (cm) - 5 × age (years) + 5 -
For women:
BMR = 10 × weight (kg) + 6.25 × height (cm) - 5 × age (years) - 161
2. Harris-Benedict Equation (older, less accurate)
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For men:
BMR = 66.47 + 13.75 × weight (kg) + 5.003 × height (cm) - 6.755 × age (years) -
For women:
BMR = 655.1 + 9.563 × weight (kg) + 1.850 × height (cm) - 4.676 × age (years)
Our calculator uses the Mifflin-St Jeor formula by default for best accuracy.
How to Use This BMR Calculator
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Enter your weight (kg or lbs).
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Enter your height (cm or ft/in).
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Enter your age (years).
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Select your gender.
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Click Calculate.
You’ll get your estimated BMR calories burned at rest.
How to Use BMR for Your Goals
Once you know your BMR, adjust it by your activity level to get your Total Daily Energy Expenditure (TDEE):
| Activity Level | Description | Multiplier |
|---|---|---|
| Sedentary | Little or no exercise | BMR × 1.2 |
| Lightly active | Light exercise/sports 1–3 days/week | BMR × 1.375 |
| Moderately active | Moderate exercise/sports 3–5 days/week | BMR × 1.55 |
| Very active | Hard exercise/sports 6–7 days/week | BMR × 1.725 |
| Extra active | Very hard exercise or physical job | BMR × 1.9 |
Your TDEE is the estimated calories you burn daily including activities.
Why Is BMR Different for Everyone?
BMR varies because of factors like:
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Age: BMR declines as you get older.
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Gender: Men tend to have more muscle, raising BMR.
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Body composition: More muscle increases BMR, fat lowers it.
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Genetics: Some people naturally have faster or slower metabolisms.
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Hormones: Thyroid hormones affect metabolism rates.
Difference Between BMR and RMR
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BMR (Basal Metabolic Rate): Calories burned at complete rest, usually measured under strict lab conditions.
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RMR (Resting Metabolic Rate): Calories burned at rest but less strict conditions (more practical for daily use).
Our calculator estimates BMR, but RMR numbers are usually 10% higher.
What Affects Your Metabolism?
Several factors can speed up or slow down metabolism:
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Muscle mass: More muscle = higher metabolism.
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Physical activity: Exercise temporarily boosts metabolism.
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Diet: Protein-rich diets increase calorie burn (thermic effect).
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Sleep quality: Poor sleep can lower metabolic rate.
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Stress: High stress can disrupt metabolism.
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Medications and health conditions: Some slow down metabolism (e.g., hypothyroidism).
How to Increase Your BMR Naturally
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Build muscle with resistance training.
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Eat enough protein daily.
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Stay active throughout the day.
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Get sufficient, quality sleep.
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Avoid crash diets—starvation lowers BMR.
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Manage stress through mindfulness and relaxation.
Common Uses of BMR Calculator
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Designing personalized diet plans.
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Estimating calorie needs for weight loss or gain.
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Planning nutrition for athletes.
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Monitoring metabolism changes over time.
How Accurate is This BMR Calculator?
While we use scientifically validated formulas, remember:
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It’s an estimate, not a medical measurement.
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For precise metabolic rate, clinical tests (like indirect calorimetry) are needed.
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Use the result as a starting point and adjust based on real-world progress.
FAQs
1. What is Basal Metabolic Rate (BMR)?
BMR is the number of calories your body needs to maintain basic functions at complete rest.
2. How does age affect BMR?
BMR decreases with age because of muscle loss and hormonal changes.
3. Can I use this calculator if I’m pregnant?
This calculator is not designed for pregnant women. Consult your healthcare provider.
4. How often should I recalculate my BMR?
Recalculate after significant weight or muscle mass changes or annually for accuracy.
5. How is BMR different from TDEE?
BMR is calories burned at rest. TDEE includes all activities throughout the day.