What is BMR and why is it important?

BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest to maintain basic functions like breathing, circulation, and cell production. It's important because it's the foundation for calculating TDEE (Total Daily Energy Expenditure) and planning weight loss or gain.

How is BMR different from TDEE?

BMR is calories burned at rest only. TDEE includes BMR plus calories burned from daily activities, exercise, and digestion. TDEE is always higher than BMR. To calculate TDEE, multiply BMR by an activity level multiplier (1.2 to 1.9).

What factors affect BMR?

BMR is affected by age (decreases with age), gender (males typically higher), weight (heavier = higher), height (taller = higher), muscle mass (muscle burns more), genetics, hormones, and metabolic health. The Harris-Benedict formula accounts for the main factors.

Why does my BMR decrease with age?

BMR decreases approximately 2% per decade after age 30 due to loss of muscle mass, hormonal changes, and mitochondrial function decline. This is why maintaining muscle through strength training becomes increasingly important as you age.

Can I increase my BMR?

Yes, you can increase BMR through: building muscle mass (muscle tissue burns more calories), strength training, maintaining adequate protein intake, getting sufficient sleep, managing stress, staying hydrated, and avoiding extreme calorie restriction. Muscle is metabolically active, so more muscle = higher BMR.

Is the BMR calculation accurate?

The Harris-Benedict formula is reasonably accurate (typically within 10-20%) for most people. However, individual BMR varies based on muscle mass, genetics, and metabolic adaptation. The calculator provides a good estimate to use as a starting point, but adjust based on real results.

BMR Calculator

Calculate your Basal Metabolic Rate - the calories you burn at complete rest

Your Information

Your BMR Results

Your BMR

1998 cal/day

Calories burned at rest

Weekly BMR Burn

13983 cal/week

Total weekly burn

Tip: Your BMR of 1998 calories is what you burn at complete rest. Add daily activities and exercise to calculate your total daily energy expenditure (TDEE) using the TDEE Calculator.

Factors Affecting Your BMR

Your BMR is influenced by several factors:

Fixed Factors

Age: 30 years (decreases ~2% per decade)
Gender: Male
Height: 5'10"
Weight: 180 lbs

Variables You Can Change

Build muscle (most effective)
Get adequate sleep (7-9 hours)
Manage stress levels
Stay hydrated

Related Tools

Use these calculators to optimize your nutrition:

TDEE Calculator Calorie Calculator Body Fat Calculator

Understanding Basal Metabolic Rate

What is BMR?

Your Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to maintain essential functions. These functions include breathing, circulation, cell production, and maintaining body temperature. It's the minimum energy your body needs just to stay alive.

BMR Includes Energy for:

Breathing and oxygen transport
Maintaining heart rate and circulation
Cell production and repair
Maintaining body temperature
Organ function (brain, kidneys, liver)
Muscle maintenance

BMR vs TDEE

Many people confuse BMR with TDEE. Here's the key difference:

BMR (Basal Metabolic Rate): Calories burned at complete rest, doing nothing. Just the minimum your body needs.

TDEE (Total Daily Energy Expenditure): All calories burned daily including BMR + activities + exercise + digestion. This is what you actually burn.

Relationship: TDEE = BMR × Activity Level Multiplier (1.2 to 1.9)

The Harris-Benedict Formula

This calculator uses the Harris-Benedict formula, one of the most accurate methods for estimating BMR:

For Males:

BMR = 88.362 + (4.8871 × height cm) + (14.4454 × weight kg) - (4.6361 × age)

For Females:

BMR = 447.593 + (3.098 × height cm) + (9.247 × weight kg) - (4.3 × age)

Example BMR Calculations

Example 1: Male, 30 years, 5'10", 180 lbs

Calculation:

Height: 5'10" = 177.8 cm
Weight: 180 lbs = 81.6 kg
BMR = 88.362 + (4.8871 × 177.8) + (14.4454 × 81.6) - (4.6361 × 30)
BMR = 88.362 + 869.08 + 1,178.95 - 139.08 = 1,997 calories/day

Example 2: Female, 28 years, 5'5", 140 lbs

Calculation:

Height: 5'5" = 165.1 cm
Weight: 140 lbs = 63.5 kg
BMR = 447.593 + (3.098 × 165.1) + (9.247 × 63.5) - (4.3 × 28)
BMR = 447.593 + 511.31 + 586.98 - 120.4 = 1,425 calories/day

Factors That Affect BMR

Factors You Can't Change:

Age: BMR decreases ~2% per decade after age 30
Gender: Males typically have 5-10% higher BMR than females
Height: Taller people have higher BMR due to greater surface area
Genetics: Natural variations in metabolism (±20%)

Factors You Can Change:

Muscle Mass: Most effective - muscle tissue burns ~3x more calories than fat
Sleep: Poor sleep (7-9 hours) can decrease BMR by 10-15%
Stress: High stress increases cortisol, which can lower BMR
Hydration: Dehydration can slow metabolism
Calorie Intake: Very low calories trigger metabolic adaptation (lower BMR)
Hormones: Thyroid function, sex hormones affect BMR

How to Use This Calculator

Step 1: Select Your Gender

Choose male or female. BMR calculations differ due to natural metabolic differences between genders.

Step 2: Enter Your Age

Input your age in years. Age affects BMR - it decreases about 2% per decade after age 30.

Step 3: Enter Your Height

Input your height in feet and inches. Taller individuals have higher BMR due to greater body surface area.

Step 4: Enter Your Weight

Input your current weight in pounds. Heavier individuals burn more calories at rest due to larger body mass.

Step 5: Review Your Results

The calculator displays your BMR (daily) and weekly burn. Your BMR is the foundation for calculating TDEE. To find your total daily calorie burn, use the TDEE Calculator and multiply your BMR by your activity level multiplier.

Common Questions About BMR

Q: Why is BMR important for weight loss?

BMR is important because it determines your baseline calorie needs. Your TDEE (what you actually burn) is calculated by multiplying your BMR by your activity level. Knowing your BMR helps you determine how many calories to eat for weight loss, maintenance, or gain.

Q: Is the BMR calculation 100% accurate?

The Harris-Benedict formula is quite accurate (typically within 10-20% for most people), but individual variation exists based on muscle mass, genetics, hormones, and metabolic health. Use this as a starting estimate, then adjust based on real results after 2-3 weeks.

Q: Can I change my BMR?

Yes, you can increase your BMR by building muscle (most effective), getting adequate sleep, managing stress, staying hydrated, and eating enough calories. You cannot significantly change age or gender, but you can optimize the factors within your control.

Q: Should I eat my BMR or my TDEE?

You should base your calorie intake on your TDEE, not your BMR. Your TDEE includes all daily activities and exercise, while BMR is only rest metabolism. Eating at your BMR would create an extreme calorie deficit. Use TDEE as your baseline, then adjust from there.

Q: Why does BMR decrease with age?

BMR decreases with age due to: loss of muscle mass (natural decline), reduction in hormones like growth hormone and testosterone, decreased mitochondrial efficiency, and reduced cellular activity. This is why maintaining muscle through strength training becomes increasingly important as you age.

Pro Tips for Optimizing Your BMR

Build Muscle: Strength training 3-4x/week increases BMR most effectively
Prioritize Sleep: 7-9 hours nightly supports metabolism and recovery
Eat Enough: Very low calories trigger metabolic adaptation (slows BMR)
Include Protein: Protein has higher thermic effect than carbs or fats
Stay Active: Regular movement increases TDEE beyond BMR
Manage Stress: High cortisol can suppress BMR
Recalculate: BMR changes with weight - recalculate every 4-6 weeks

Quick Reference

BMR by Gender:

Males: Typically 5-10% higher than females
Females: Typically lower due to less muscle mass

Age Effect:

BMR decreases ~2% per decade after age 30

BMR to TDEE:

Sedentary: BMR × 1.2
Lightly Active: BMR × 1.375
Moderately Active: BMR × 1.55
Very Active: BMR × 1.725
Extremely Active: BMR × 1.9

What Affects BMR

Increases BMR:

• Building muscle
• Youth
• Adequate calories
• Good sleep
• Stress management

Decreases BMR:

• Age (after 30)
• Low calories
• Muscle loss
• Poor sleep
• High stress

Understanding TDEE

BMR: Calories at complete rest only

TDEE: BMR + all daily activities + exercise

Use TDEE for weight loss/gain calculations, not BMR