BMR Calculator – Calculate Your Basal Metabolic Rate
Calculate your Basal Metabolic Rate — the minimum calories your body needs to function at complete rest.
💡 Coach Tip: BMR is your metabolic floor. Never eat below this number for extended periods, or you risk metabolic adaptation and muscle loss. Use TDEE for daily targets.
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We'll calculate using two trusted formulas
Your BMR Results
Calories burned at complete rest
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What is a BMR Calculator and Who Should Use One?
A BMR calculator estimates your Basal Metabolic Rate — the number of calories your body burns each day simply to keep you alive, without any physical activity. This includes energy used for breathing, blood circulation, cell repair, and temperature regulation. BMR is your metabolic baseline and the foundation upon which all calorie planning is built.
Understanding your resting calorie burn is essential for anyone setting nutrition targets. Nutritionists, personal trainers, and dietitians use BMR as the starting point for calculating TDEE and building client meal plans. Athletes use it to ensure they never diet below their metabolic floor. And beginners use it to understand why no single calorie number fits everyone — your BMR is unique to your age, gender, height, and weight.
This calculator uses two trusted metabolism formulas: the Mifflin-St Jeor equation (the most accurate for modern populations) and the Harris-Benedict equation (an older but still widely referenced formula). Both are displayed so you can compare, though we recommend using Mifflin-St Jeor as your primary number.
Once you know your BMR, the next step is calculating your TDEE — your total calorie burn including activity — using our TDEE Calculator. From there, you can create a precise calorie plan for fat loss, muscle gain, or maintenance. Never sustain a diet below your BMR without medical supervision, as doing so risks metabolic adaptation and muscle loss.
How to Use This BMR Calculator
- Select your unit system (metric or imperial) and enter your age, gender, weight, and height.
- Click "Calculate My BMR" to see your resting calorie burn using both the Mifflin-St Jeor and Harris-Benedict formulas.
- Click on either result card to select that formula as your working BMR.
- Use your BMR result as input for our TDEE Calculator to find your full daily calorie needs.
- Recalculate every 8–12 weeks or after significant changes in body weight or composition.
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What is BMR (Basal Metabolic Rate)?
BMR is the number of calories your body burns while at complete rest — just to keep you alive. It powers essential functions like breathing, blood circulation, cell production, and temperature regulation.
BMR accounts for approximately 60-75% of your total daily calorie expenditure, making it the largest component of your energy needs.
BMR Formulas Explained
Mifflin-St Jeor (1990)
Most accurate for modern populations. Developed using indirect calorimetry data and validated across diverse groups.
Harris-Benedict (1918/1984)
One of the oldest formulas. Revised in 1984 but may still overestimate needs by 5-10% for average individuals.
What To Do After Calculating BMR
Calculate Your TDEE
Multiply BMR by your activity factor to get total daily calories burned.
Go to Calculator →Plan Your Macros
Break down calories into protein, carbs, and fat for optimal results.
Go to Calculator →