BMR Calculator
Calculate your Basal Metabolic Rate (BMR) and estimated daily energy expenditure using the Mifflin-St Jeor formula. Free in your browser.
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How to use BMR Calculator
- 1
Enter your weight, height, age, and biological sex.
- 2
Select your daily physical activity multiplier.
- 3
Click Calculate to estimate your Basal Metabolic Rate and resting energy.
Capabilities
- Calculates baseline Basal Metabolic Rate (BMR) via Mifflin-St Jeor
- Estimates daily caloric burn across physical activity multipliers
- Private browser evaluation with zero server tracking
How Basal Metabolic Rate (BMR) & Resting Energy Expenditure Work
Your Basal Metabolic Rate (BMR) accounts for approximately 60% to 75% of your total daily caloric expenditure. Knowing your resting baseline provides the foundational starting point for calculating energy balance, fitness nutrition, and weight management programs.
Calculations represent mathematical models derived from the Mifflin-St Jeor formula. Actual metabolic rates differ based on individual thyroid function, body fat percentage, and genetic variation. Use results as reference estimates rather than medical prescriptions.
• Male: BMR = 10*Weight + 6.25*Height - 5*Age + 5
• Female: BMR = 10*Weight + 6.25*Height - 5*Age - 161 (Weight in kg, height in cm).
Multiplying baseline BMR by physical activity multipliers (1.2 for sedentary desk routines up to 1.725 for intense athletic regimens) estimates total daily energy expenditure.
Worked Example: 25-Year-Old Male (70 kg, 170 cm)
Suppose a 25-year-old male with a weight of 70 kg and height of 170 cm leads a sedentary lifestyle:
Baseline BMR Calculation: 10(70) + 6.25(170) - 5(25) + 5 = 700 + 1062.5 - 125 + 5 = 1,643 kcal/day
Sedentary Daily Expenditure (1.2 factor): 1,643 * 1.2 = 1,972 kcal/day
Summary: The body burns approximately 1,643 calories at complete rest and about 1,972 calories with light sedentary daily movement.
For structured maintenance and illustrative deficit targets across activity levels, use Calorie Calculator.
This tool operates in a sandbox directly inside your web browser. All parsing, processing, and downloads are rendered locally. Your file size, metadata, and contents never cross the network. It works completely offline.
Frequently Asked Questions
What is Basal Metabolic Rate (BMR)?
Basal Metabolic Rate (BMR) is the estimated minimum number of calories your body burns in 24 hours to maintain essential physiological functions (cellular respiration, circulation, temperature regulation, and brain activity) while at complete physical and digestive rest.
Which formula does this BMR calculator use?
This calculator implements the Mifflin-St Jeor equation, widely regarded in clinical dietetics as one of the most reliable formulaic estimates of resting metabolic rate in adults.
What is the difference between BMR and TDEE?
BMR represents calories burned doing nothing at all. Total Daily Energy Expenditure (TDEE) accounts for your physical movement by multiplying BMR by an activity factor (such as 1.2 for sedentary or 1.55 for moderate exercise).
Can increasing muscle mass raise my BMR?
Yes. Skeletal muscle is metabolically active tissue that requires more energy to sustain at rest than adipose fat tissue. Resistance training and lean tissue development can gradually elevate baseline metabolic rate.
Are BMR calculations an exact measurement?
No. The formula provides a mathematical estimation. Individual genetics, thyroid function, ambient temperature, and body composition cause real-world metabolic rates to vary by 5% to 15% from mathematical predictions.