Basal Metabolic Rate (BMR) Calculator
Discover how many calories your body burns just to exist. Your BMR is the foundation of every successful diet and fitness plan.
Resting Burn
Calories at zero activity
TDEE
Daily energy expenditure
Mifflin-St Jeor
Gold standard formula
Diet Baseline
Start point for plans
What is Basal Metabolic Rate?
Your BMR represents the number of calories your body needs to perform basic life-sustaining functions like breathing, circulation, and cell production.
The "Coma" Calories
Think of BMR as the amount of energy you would burn if you stayed in bed all day without moving. It accounts for about 60-70% of the calories you burn daily. It is the absolute minimum energy requirement for survival.
Organ Function
Your brain, liver, kidneys, and heart consume calories 24/7.
Body Composition
Muscle tissue burns more calories at rest than fat tissue, influencing your BMR.
Foundation for Dieting
You generally should not eat below your BMR, or your metabolism may slow down.
Personalized Stats
Calculates based on your specific age, gender, height, and weight for high accuracy.
TDEE Insight
We also calculate your Total Daily Energy Expenditure to show what you actually burn with movement.
Scientifically Backed
Uses the Mifflin-St Jeor equation, currently considered the most accurate predictive formula.
Why Choose Our BMR Calculator?
Clinical Accuracy
We use the industry-standard Mifflin-St Jeor equation, preferred by dietitians over the older Harris-Benedict formula.
Full Energy Breakdown
We don't just stop at BMR; we calculate your TDEE for 5 different activity levels so you can plan your diet effectively.
Privacy Guaranteed
Your weight, age, and height data are processed instantly in your browser and never stored on our servers.
Calculate Your BMR
Enter your details to find your metabolic baseline.
How to Use the BMR Calculator
Find your baseline in three simple steps.
Select Gender & Units
Men and women have different metabolic rates due to muscle mass variance. Choose your gender and whether you prefer Metric (kg/cm) or Imperial (lbs/ft).
Enter Body Stats
Input your current age, weight, and height. These are the primary variables in the Mifflin-St Jeor formula used to estimate your metabolic output.
Analyze Results
Click Calculate. You will see your BMR (calories at rest). Below that, we provide a table showing how many calories you need to maintain your weight based on different activity levels.
BMR vs. RMR vs. TDEE
Understanding the alphabet soup of metabolism.
BMR
Basal Metabolic Rate
The minimum calories required for basic survival functions (breathing, cell production) while in a strictly rested, fasting, and temperate state. It is the absolute floor of energy expenditure.
RMR
Resting Metabolic Rate
Similar to BMR but measured under less strict conditions (e.g., not fasting). It includes the energy used for digestion and non-exercise movements. Often used interchangeably with BMR.
TDEE
Total Daily Energy Expenditure
The total calories you burn in a day. It equals your BMR + Activity + Thermic Effect of Food. This is the number you need to know for weight loss or gain.
Factors Affecting Your BMR
Why does your friend eat more than you but not gain weight?
Muscle Mass
Muscle burns more calories than fat, even at rest. More muscle = Higher BMR.
Age
Metabolism naturally slows down as you age, mostly due to loss of muscle tissue.
Gender
Men usually have a faster metabolism than women due to larger body size and muscle mass.
Genetics
Your genetic makeup determines your baseline metabolic speed.
The Mifflin-St Jeor Equation
The formula used in this calculator, introduced in 1990, is considered the most accurate standard for estimating BMR.
For Men
BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5
For Women
BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161
Understanding Daily Maintenance (TDEE)
Your Total Daily Energy Expenditure (TDEE) is your BMR multiplied by an activity factor. Choose the description that best fits your lifestyle.
Sedentary
Multiplier: 1.2
Little to no exercise. Desk job, driving commute, and relaxing at home. Most office workers fall here.
Lightly Active
Multiplier: 1.375
Light exercise or sports 1-3 days/week. Or a job that involves some standing/walking (teacher, retail).
Moderately Active
Multiplier: 1.55
Moderate exercise 3-5 days/week. Or a relatively active lifestyle combined with gym sessions.
Very Active
Multiplier: 1.725
Hard exercise 6-7 days/week. Consistent high-intensity training or a physically demanding job.
Extra Active
Multiplier: 1.9
Physical job (construction) AND daily hard exercise. Or professional athlete training twice a day.
Applications of BMR
Why do you need to know this number?
Weight Loss
BMR helps you establish a safe calorie deficit. Knowing your baseline ensures you don't under-eat (which harms metabolism) or over-eat while thinking you are dieting.
Bulking & Muscle Gain
To build muscle, you often need a caloric surplus. BMR + Activity gives you the maintenance number, so you know exactly how much more to eat to grow.
BMR in Action
See how BMR and TDEE numbers are used to create actual diet plans for different goals.
Case Study: Sarah (Weight Loss)
Sedentary Office Worker
Sarah needs a 500 calorie deficit.
Target: 1,276 kcal/day (Safe weight loss).
Case Study: Mike (Muscle Gain)
Active Athlete
Mike needs a surplus to build muscle.
Target: 3,400 kcal/day (+250 kcal surplus).
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Frequently Asked Questions
Can I increase my BMR?
Yes. The most effective way is to increase muscle mass through resistance training. Muscle tissue burns more calories at rest than fat tissue.
Should I eat below my BMR to lose weight?
Generally, no. Consistently eating below your BMR can send your body into "starvation mode," slowing your metabolism and causing muscle loss. Aim to eat between your BMR and TDEE.
Does BMR change daily?
Your BMR is relatively stable but decreases slowly as you age or lose weight. It can fluctuate slightly with hormonal changes, illness (fever raises BMR), or extreme temperatures.
Why are there different formulas?
Formulas like Harris-Benedict were created decades ago. The Mifflin-St Jeor equation is newer (1990) and has been found to be more accurate for modern lifestyles and body compositions.