Before estimating daily calorie needs, it helps to know how much energy the body would use at rest. BMR, or basal metabolic rate, is an estimate of the calories required for essential functions such as circulation, breathing, and temperature regulation over a day.
This BMR Calculator uses the inputs and equation shown on the page to estimate resting energy expenditure. BMR is not the same as total daily calorie use: walking, training, work, digestion, and other activity add energy demand above the basal level. Equation-based results are useful for planning and education, but individual metabolism can differ because of body composition, health, medications, pregnancy, and other factors.
How to use this tool
How is BMR estimated?
One widely used method is the Mifflin–St Jeor equation. Male estimate: BMR = 10W + 6.25H − 5A + 5. Female estimate: BMR = 10W + 6.25H − 5A − 161, where W is kilograms, H is centimeters, and A is age in years.
How to use BMR Calculator
- Enter the age, sex, height, and weight requested by the calculator.
- Keep height and weight units consistent with the selected measurement system.
- Calculate the estimated basal metabolic rate.
- Use the result as an estimate of energy expenditure at rest, not as an exact daily calorie requirement.
- If the result will guide a health or nutrition decision, interpret it with appropriate professional context.
BMR versus TDEE
BMR represents baseline energy use under resting conditions. TDEE adds the energy associated with movement, exercise, food processing, and daily activity, so it is normally higher.
Methodology reference
The Mifflin–St Jeor resting-energy equation is documented in clinical nutrition references. Reference: NCBI Bookshelf – Mifflin–St Jeor equation.
Examples
Mifflin–St Jeor male example
BMR ≈ 10×80 + 6.25×180 − 5×30 + 5 = 1,780 kcal/day.
Mifflin–St Jeor female example
BMR ≈ 10×60 + 6.25×165 − 5×30 − 161 = 1,320 kcal/day.
Effect of age
The age term is subtracted in the equation, so the older input produces a lower estimate when other inputs stay constant.
BMR versus TDEE
1,600 is not the full-day maintenance target; activity and digestion raise total daily expenditure above basal needs.
Common use cases
- Understanding resting energy needs
- Nutrition education
- Starting TDEE calculations
- Fitness planning
- Weight-management discussions
Frequently asked questions
What does BMR mean?
Basal metabolic rate is an estimate of the energy your body uses at rest to support basic physiological functions. It is not the same as total daily energy expenditure.
Which formula does this BMR estimate use?
The page describes the Mifflin–St Jeor equation, which estimates BMR from age, sex, height, and weight. It is a population-based estimate rather than a direct metabolic measurement.
What is the difference between BMR and TDEE?
BMR estimates resting energy use. TDEE adds activity and other daily energy expenditure, so it is normally higher than BMR.
Why can my actual calorie needs differ from BMR?
Body composition, health, medications, environment, activity, and individual metabolic variation can make real energy expenditure differ from a prediction equation.
Can I use BMR as a daily calorie target?
Not by itself. BMR represents resting energy expenditure, not the full energy needed for ordinary daily activity.
Why can another BMR calculator show a different result?
Different calculators may use a different equation, unit conversion, sex category, or rounding rule. Compare the methodology before comparing the final number.