BMR Calculator - Calculate Basal Metabolic Rate

BMR Calculator

Calculate Your Basal Metabolic Rate

Calculate Your BMR

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Calories per day at rest

What is BMR?

Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to maintain vital functions like breathing, circulation, and cell production. It represents 60-75% of your total daily calorie expenditure and is influenced by age, gender, body composition, and genetics.

BMR Calculation Formulas

This calculator uses the Mifflin-St Jeor equation, considered the most accurate for general populations:

  • Men: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) + 5
  • Women: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) - 161

Factors Affecting Your BMR

  • Muscle Mass: More muscle = higher BMR (muscle burns more calories than fat)
  • Age: BMR decreases about 2% per decade after age 30
  • Gender: Men typically have 5-10% higher BMR due to more muscle mass
  • Genetics: Some people naturally have faster or slower metabolisms
  • Body Size: Larger bodies require more energy to function

How to Use Your BMR

BMR is the foundation for calculating your Total Daily Energy Expenditure (TDEE). To determine your actual calorie needs, multiply your BMR by an activity factor (1.2 for sedentary to 1.9 for very active). Use BMR to set calorie targets for weight loss, maintenance, or muscle gain.

Frequently Asked Questions

What's the difference between BMR and TDEE? +

BMR is calories burned at complete rest, while TDEE (Total Daily Energy Expenditure) includes all activities. TDEE = BMR × activity multiplier. For example, if your BMR is 1,500 and you're moderately active, your TDEE = 1,500 × 1.55 = 2,325 calories.

Which BMR formula is most accurate? +

The Mifflin-St Jeor equation (used in this calculator) is considered most accurate for the general population with about 90% accuracy. The Katch-McArdle formula is more accurate if you know your body fat percentage, as it accounts for lean body mass.

Can I increase my BMR? +

Yes! Building muscle through strength training is the most effective way to increase BMR since muscle tissue burns more calories at rest than fat. Other factors include eating enough protein, staying hydrated, getting adequate sleep, and avoiding extreme calorie restriction which can lower BMR.

Why is my BMR lower than expected? +

Several factors can lower BMR: aging (2% decrease per decade after 30), prolonged calorie restriction, loss of muscle mass, hormonal imbalances (thyroid issues), or genetics. If concerned, consult a healthcare provider to rule out medical causes. Focus on building muscle and eating adequate calories to support a healthy metabolism.