BMR Calculator Online – Calculate Your Basal Metabolic Rate

Use this free BMR calculator to determine how many calories your body burns at rest. Calculate your Total Daily Energy Expenditure (TDEE) based on your activity level for accurate calorie planning.

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Activity Level

What is BMR (Basal Metabolic Rate)?

BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest to maintain vital functions like breathing, circulation, and cell production. This BMR calculator online helps you understand your baseline calorie needs for effective weight management.

How to calculate BMR

This calculator uses the Mifflin-St Jeor equation, which is considered one of the most accurate:

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

What is TDEE (Total Daily Energy Expenditure)?

TDEE is your total calorie burn per day, including all activities. It's calculated by multiplying your BMR by an activity factor:

  • Sedentary (×1.2): Little or no exercise, desk job
  • Lightly Active (×1.375): Light exercise 1-3 days/week
  • Moderately Active (×1.55): Moderate exercise 3-5 days/week
  • Very Active (×1.725): Hard exercise 6-7 days/week
  • Extra Active (×1.9): Very intense exercise or physical job

How to use this BMR calculator

  1. Select your biological sex (male or female)
  2. Enter your age in years
  3. Enter your weight in kilograms
  4. Enter your height in centimeters
  5. Select your typical activity level
  6. Click Calculate to see your BMR and TDEE

Using BMR for weight management

  • Weight loss: Consume 300-500 calories below your TDEE for gradual, sustainable weight loss (0.5-1 lb/week)
  • Weight maintenance: Consume calories equal to your TDEE to maintain current weight
  • Weight gain: Consume 300-500 calories above your TDEE for healthy weight gain (muscle building)
  • Extreme deficit caution: Never consume fewer calories than your BMR for extended periods

Factors that affect BMR

  • Age: BMR decreases by about 2% per decade after age 30
  • Muscle mass: More muscle = higher BMR (muscle burns more calories than fat)
  • Body composition: Higher body fat percentage typically means lower BMR
  • Genetics: Some people naturally have faster or slower metabolism
  • Hormones: Thyroid function and other hormones significantly impact BMR
  • Temperature: Cold environments slightly increase BMR
  • Diet: Severe calorie restriction can lower BMR over time

Tips for boosting your metabolism

  • Build muscle through strength training (increases BMR permanently)
  • Stay physically active throughout the day
  • Eat enough protein (higher thermic effect than carbs or fats)
  • Don't skip meals or drastically cut calories
  • Get adequate sleep (7-9 hours per night)
  • Stay hydrated (drinking water can temporarily boost metabolism)
  • Eat spicy foods occasionally (capsaicin can slightly increase calorie burn)
  • Drink green tea or coffee in moderation

BMR vs RMR: What's the difference?

BMR (Basal Metabolic Rate) is measured under very strict laboratory conditions after 8 hours of sleep and 12 hours of fasting. RMR (Resting Metabolic Rate) is measured under less strict conditions and is typically 10-20% higher than BMR. For practical purposes, most calculators (including this one) estimate BMR, which approximates RMR closely enough for diet planning.

Frequently Asked Questions

Click a question to view the answer below.

What is a normal BMR?

Average BMR varies widely based on age, sex, and body composition. For adults, BMR typically ranges from 1,200-2,400 calories per day. Men generally have higher BMR than women due to greater muscle mass. Your individual BMR is normal if it reflects your body's needs.

Should I eat less than my BMR to lose weight?

No, it's not recommended to consistently eat below your BMR. Your BMR represents the minimum calories your body needs for vital functions. Eating below BMR for extended periods can slow metabolism, cause muscle loss, and lead to nutrient deficiencies. Instead, eat below your TDEE but above your BMR.

How accurate is this BMR calculator?

This calculator uses the Mifflin-St Jeor equation, which is accurate for most people within ±10%. However, it's an estimate. Actual BMR varies based on factors like muscle mass, genetics, and hormones. For precise measurements, consider professional metabolic testing.

Does BMR change with age?

Yes, BMR naturally decreases with age, approximately 2% per decade after age 30. This is primarily due to muscle loss and hormonal changes. However, maintaining muscle mass through strength training can help minimize this decline.

Can I increase my BMR permanently?

Yes! The most effective way to permanently increase BMR is to build muscle through strength training. Muscle tissue burns more calories at rest than fat tissue. Each pound of muscle burns about 6 calories per day at rest, while fat burns only 2 calories.

What's the difference between BMR and calories burned?

BMR is the calories you burn at complete rest. Total calories burned (TDEE) includes BMR plus all physical activity, digestion, and daily movement. TDEE is always higher than BMR and represents your actual daily calorie needs.