Skip to main content

🔥 BMR Calculator

Estimate basal metabolic rate using the Mifflin-St Jeor formula

Your estimated BMR
1568 kcal/day
Sedentary1881 kcal
Lightly Active2155 kcal
Moderately Active2430 kcal
Very Active2704 kcal
Extra Active2978 kcal

Mifflin-St Jeor Formula:

Male: 10×weight + 6.25×height - 5×age + 5

Female: 10×weight + 6.25×height - 5×age - 161

Related Calculators

📉Calorie Deficit Calculator🔥TDEE Calculator🍎Calorie Calculator🥗Macro Calculator🔋Energy Converter⚖️BMI Calculator

BMR Calculator Guide

Basal Metabolic Rate (BMR) is the number of calories your body needs at complete rest to maintain basic physiological functions such as breathing, heartbeat, blood circulation, cell repair, and temperature regulation.

BMR accounts for 60-70% of total daily energy expenditure. This calculator uses the Mifflin-St Jeor formula, which was developed in 1990 and is widely regarded as the most accurate BMR estimation formula for modern populations.

Mifflin BMR Formula

Male BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age(years) + 5
Female BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age(years) - 161

Example (30-year-old male, 70kg, 170cm):
BMR = 10×70 + 6.25×170 - 5×30 + 5
BMR = 700 + 1062.5 - 150 + 5 = 1617.5 ≈ 1618 kcal/day

Understanding Basal Metabolism

Basal metabolism is the body's baseline energy cost. Even at complete rest, the body requires significant energy to maintain vital functions. Factors that affect BMR include:

• Genetics: Some individuals naturally have faster or slower metabolism • Sex: Males typically have 5-10% higher BMR (due to greater muscle mass) • Age: BMR decreases approximately 1-2% per decade • Body size: Larger individuals have higher BMR • Muscle mass: Muscle tissue burns 3-5 times more calories than fat tissue • Hormones: Thyroid hormones significantly affect metabolic rate • Temperature: Cold environments increase BMR to maintain body temperature • Nutrition: Prolonged calorie restriction can decrease BMR by 10-15%

BMR Calculation Examples

📋
Example 1: 30-year-old male office worker Input: male, 75kg, 178cm, 30 years BMR = 10×75 + 6.25×178 - 5×30 + 5 = 750 + 1112.5 - 150 + 5 = 1718 kcal/day Estimated TDEE at different activity levels: - Sedentary (×1.2): 2062 kcal/day - Lightly active (×1.375): 2362 kcal/day - Moderately active (×1.55): 2663 kcal/day Example 2: 28-year-old active female Input: female, 55kg, 165cm, 28 years BMR = 10×55 + 6.25×165 - 5×28 - 161 = 550 + 1031.25 - 140 - 161 = 1280 kcal/day Estimated TDEE at different activity levels: - Sedentary (×1.2): 1536 kcal/day - Moderately active (×1.55): 1984 kcal/day - Very active (×1.725): 2208 kcal/day

BMR Estimation Limitations

💡
The Mifflin formula is suitable for most healthy adults but may not be accurate for: • Athletes with very high muscle mass (formula may underestimate BMR) • Extremely obese individuals (BMI > 40) • Pregnant or breastfeeding women For more precise BMR measurement, indirect calorimetry (respiratory gas analysis) is the clinical gold standard. TDEE (Total Daily Energy Expenditure) = BMR × activity multiplier. This calculator provides TDEE estimates at 5 activity levels for reference.

Common Use Cases for BMR

  • - Establishing calorie intake baselines for weight management
  • - Understanding individual metabolic differences
  • - Estimating TDEE for nutrition planning
  • - Tracking changes in metabolism over time

BMR Formula Comparison: Mifflin vs Harris-Benedict

Several BMR formulas exist with different strengths:

① Mifflin-St Jeor (1990): Most accurate for modern populations. Recommended by the Academy of Nutrition and Dietetics. Best for overweight and obese individuals.

② Harris-Benedict (1919, revised 1984): Historically widely used but may overestimate BMR by 3-5% for modern populations.

③ Katch-McArdle: Requires body fat percentage input. Calculates based on lean body mass. Most accurate when body fat is known.

For general use, the Mifflin formula is recommended. If body fat percentage is available, Katch-McArdle may provide more precise results.

FAQ

Ad Slot