Free BMR Calculator
Basal Metabolic Rate from the Mifflin–St Jeor equation.
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BMR
1,649 kcal/day
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Short answer
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to maintain vital functions. The Mifflin–St Jeor equation estimates BMR from sex, weight, height, and age.
What is the BMR Calculator?
BMR is the minimum energy your body needs at rest — for breathing, circulating blood, and maintaining body temperature. It typically accounts for 60–75% of daily calorie use.
How does the BMR Calculator work?
Multiply body weight in kilograms by 10, height in centimeters by 6.25, and age by 5. Sum the first two and subtract age and the sex adjustment. The result is calories per day at zero activity.
Formula
Variables
kgWeight in kilogramscmHeight in centimetersageAge in yearssSex constant
Explanation
The Mifflin–St Jeor equation, published in 1990, is considered more accurate than the older Harris–Benedict for modern populations.
Examples
Example 1: 30-year-old male, 175 cm, 70 kg
BMR ≈ 1,649 kcal/day.
Example 2: 45-year-old female, 165 cm, 65 kg
BMR ≈ 1,290 kcal/day.
Applications
- Weight-loss calorie targets
- Nutrition planning
- Fitness coaching
Advantages
- Better accuracy than Harris–Benedict for adults
- Simple inputs
- Widely used in clinical settings
Limitations
- Assumes typical body composition — very lean or very obese people are estimated less accurately
- Does not account for medical conditions that alter metabolism
Common mistakes
- Confusing BMR with total daily energy expenditure (TDEE)
- Using activity multipliers as if they were BMR
Tips
- For weight loss, subtract ~500 kcal/day from your maintenance total
- Recalculate every 5–10 kg of weight change
Related concepts
The BMR Calculator sits inside the Health Calculators hub, in the nutrition & diet cluster. Energy targets and macronutrient planning. Understanding the terms below makes the output easier to interpret and easier to compare against neighbouring measures.
Practical use cases and industry applications
Understanding BMR
BMR is the minimum energy your body needs at rest — for breathing, circulating blood, and maintaining body temperature. It typically accounts for 60–75% of daily calorie use. Within health calculators, bmr belongs to the nutrition & diet cluster, where it shares terminology and assumptions with closely related tools.
Learning how bmr is calculated
The Mifflin–St Jeor equation, published in 1990, is considered more accurate than the older Harris–Benedict for modern populations. Working through the variables one at a time — kg, cm, age, s — makes the result reproducible by hand and easier to sanity-check.
Using bmr to make a decision
Weight-loss calorie targets Nutrition planning Fitness coaching Because outputs depend on the assumptions you enter, run more than one scenario before committing to a figure.
How bmr compares with related measures
energy balance, macronutrient split, hydration, thermic effect all describe adjacent aspects of nutrition & diet. Comparing this calculator's output against those measures — using the related tools listed on this page — prevents a single metric from being read in isolation.
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is at-rest calories only. TDEE is BMR multiplied by an activity factor and represents daily maintenance calories.
Which formula is best?
Mifflin–St Jeor is currently the most accurate general-purpose equation for adults.
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