BMR Calculator
Estimate your baseline resting metabolism and active daily energy expenditure.
Body metrics
Basal Metabolic Rate (BMR)
1,649 kcal/day
Your estimated Basal Metabolic Rate is 1,649 calories per day. This is what your body requires strictly at rest.
- TDEE: Sedentary
- 1,979 kcal/day
- TDEE: Light Exercise
- 2,267 kcal/day
- TDEE: Moderate Exercise
- 2,556 kcal/day
- TDEE: Active Training
- 2,845 kcal/day
- TDEE: Extreme Athlete
- 3,133 kcal/day
Mifflin-St Jeor Working
BMR = 10 × 70 kg + 6.25 × 175 cm − 5 × 30 yrs + 5 = 1649 kcal/dayBMR calculations are mathematical estimates. This tool does not provide medical diagnosis, metabolic screening, or personalized dietary prescriptions. Consult a qualified clinical nutritionist or physician before starting any extreme calorie restrictions.
About this calculator
Your Basal Metabolic Rate (BMR) represents the absolute minimum number of calories your body needs to maintain basic life-sustaining functions—such as breathing, circulation, and cell production—while completely at rest. This calculator utilizes the established Mifflin-St Jeor equation to estimate your baseline metabolism and active daily calorie expenditure.
How to use this calculator
Select biological sex and enter age
Select your biological sex (male or female) and input your current age. Muscle mass and hormonal factors cause metabolic baselines to vary between genders and age cohorts.
Choose unit system and enter measurements
Switch between Metric (kg, cm) and Imperial (lb, ft + inches) units. Enter your current weight and total height accurately.
Review estimated BMR and TDEE calorie tiers
Instantly view your calculated BMR in kcal/day. Examine your Total Daily Energy Expenditure (TDEE) based on varying active lifestyle categories.
Apply the metabolic context responsibly
Use the outputs to budget your target calorie intake for weight maintenance, healthy loss, or muscle gain. Read the medical disclaimers carefully.
Formula
Men: BMR = 10W + 6.25H − 5A + 5 / Women: BMR = 10W + 6.25H − 5A − 161- This calculator strictly utilizes the Mifflin-St Jeor equation, which is widely considered the most accurate standard formula for estimating adult BMR.
- W is your body weight in kilograms.
- H is your total stature in centimeters.
- A is your chronological age in years.
- BMR is calculated strictly under neutral ambient temperatures and post-absorptive states (resting and empty stomach).
Worked example
Inputs
- Sex: Male
- Age (A): 30 years
- Weight (W): 70 kg
- Height (H): 175 cm
Calculation
BMR = 10 × 70 kg + 6.25 × 175 cm − 5 × 30 yrs + 5
= 700 + 1093.75 − 150 + 5
= 1648.75
≈ 1,649 kcal/dayYour estimated Basal Metabolic Rate (BMR) is 1,649 kcal/day. This represents the energy your body burns strictly at complete rest.
What the result means
- Basal Metabolic Rate (BMR) is the flat caloric outgo your organs require to perform involuntary cellular processes.
- Total Daily Energy Expenditure (TDEE) estimates your actual daily energy expenditure by multiplying BMR by physical activity factors.
- Sedentary lifestyle (multiplier 1.2) represents normal office work with zero scheduled exercise.
- Active lifestyle tiers (multiplier 1.55 to 1.9) account for regular cardiovascular training or intense physical labour.
Related calculations
- Calculate your Body Mass Index (BMI) to screen your weight-to-stature ratio against clinical guidelines.
- Adjust age and weight variables to find out how metabolic rates naturally decrease as adults grow older.
- Project your target daily calorie budgets under active workout plans to structure a healthy body weight strategy.
Frequently asked questions
What is the Mifflin-St Jeor equation?
The Mifflin-St Jeor equation is a standardized, clinically verified formula used to estimate an individual’s Basal Metabolic Rate (BMR). Introduced in 1990 as an improvement over the older Harris-Benedict equation, it has been shown to predict resting energy expenditure with greater accuracy across modern, diverse adult populations.
What is the difference between BMR and TDEE?
BMR (Basal Metabolic Rate) is the minimum energy your body burns strictly to stay alive in a resting, post-absorptive state. TDEE (Total Daily Energy Expenditure) is the complete estimate of calories you burn over 24 hours once your active movement, workouts, walking, and the thermal effect of digesting food are added to your BMR.
How do I use my BMR to lose or gain weight?
To maintain your weight, consume calories equal to your TDEE. To lose weight safely, maintain a moderate caloric deficit by eating 300 to 500 calories less than your TDEE daily. To gain weight or muscle mass, consume a caloric surplus above your TDEE. Never consume fewer calories than your base BMR without medical supervision.
Does muscle mass affect my Basal Metabolic Rate?
Yes, muscle tissue is highly active metabolically compared to fat tissue. An individual with high lean muscle mass will burn significantly more calories at rest than someone of the same weight with higher body fat % because maintaining muscle cells requires continuous, intense thermal energy.
Why does BMR naturally decrease as we age?
As adults age, they naturally experience a gradual decline in lean muscle mass (known as sarcopenia) and progressive decreases in organ weight/activity levels. These factors slowly lower your baseline resting metabolic burn, which is why older adults typically require fewer daily calories to maintain weight.
Is a BMR calculator highly accurate for everyone?
A BMR calculator provides a mathematical estimate based on average population statistics. It does not measure your individual thyroid hormone activity, body composition (muscle vs fat ratio), or unique genetic metabolic efficiency. It should be treated as a valuable guideline, not an absolute clinical diagnostic.
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