Enter Your Details
Estimate your basal metabolic rate using the Mifflin-St Jeor formula
Your BMR Result Will Appear Here
Enter your sex, age, height, and weight, then click calculate to estimate how many calories your body may burn at rest each day.
Important BMR Guidance
This calculator uses the widely used Mifflin-St Jeor equation to estimate basal metabolic rate for general education and planning.
- Supports both metric and imperial units
- Uses sex, age, height, and weight to estimate BMR
- Explains clearly that BMR is different from TDEE
- Designed for wellness planning, not medical diagnosis
BMR is an estimate only. It does not replace professional nutrition or medical advice.
Mifflin-St Jeor BMR Formula
| Formula | Equation | Simple Meaning |
|---|---|---|
| For Men | BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5 | Estimates calories your body may use at rest each day |
| For Women | BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161 | Uses the same core variables with a different constant |
What the Formula Uses
| Factor | Why It Matters |
|---|---|
| Age | BMR often declines with age because body composition and energy needs can change over time. |
| Sex | The equation uses different constants because average body composition patterns differ. |
| Height | Taller individuals generally have greater body mass to support at rest. |
| Weight | Higher body weight often raises estimated resting energy needs. |
| Body Composition | People with more lean mass may have a higher energy expenditure at rest, even if two people weigh the same. |
What Is BMR and How Is It Calculated?
BMR, or Basal Metabolic Rate, is the estimated number of calories your body needs each day to perform basic life-sustaining functions while at complete rest. These functions include breathing, circulation, body temperature regulation, and organ function.
BMR helps show how much energy your body uses even when you are not exercising or doing daily activities. It is often used as a starting point for estimating daily calorie needs, weight management goals, and overall energy requirements.
Since BMR is only a resting estimate, your actual daily calorie needs will usually be higher once physical activity, exercise, and lifestyle factors are included.
What is BMR? BMR is your resting energy estimate, not your full daily calorie target.
What is it used for? It can help you understand your baseline calorie needs before adding activity, exercise, or goal-based nutrition planning.
Step 1: Enter Sex and Age
The Mifflin-St Jeor equation uses sex and age because resting energy needs are not the same for everyone.
Step 2: Enter Height and Weight
You can use metric or imperial units. The calculator converts measurements as needed before applying the formula.
Step 3: Apply the BMR Formula
The calculator estimates how many calories your body may burn each day at rest. This is a practical planning estimate, not a lab measurement.
Step 4: Compare BMR with Daily Needs
Your daily calorie needs are usually higher than your BMR because daily living includes activity and movement. For that next step, use a Calorie Calculator.
Step 5: Use Other Body Metrics for Better Context
BMR works even better alongside related tools such as a BMI Calculator, Body Fat Calculator, or Ideal Weight Calculator.
This tool is for educational and planning purposes only. Actual calorie needs can vary based on health status, lean mass, hormone levels, genetics, and daily activity.
BMR vs TDEE
BMR is the estimated number of calories your body burns at complete rest. TDEE, or total daily energy expenditure, includes your BMR plus the calories you burn through walking, exercise, digestion, daily tasks, and other movement.
If you want a better estimate of daily maintenance calories, continue with a Calorie Needs and TDEE Calculator.
What Affects BMR?
Common factors that affect BMR:
- Age
- Sex
- Height
- Weight
- Body composition, especially lean mass
Why this matters:
- Two people with the same weight can still have different BMR estimates
- More lean mass may raise calories burned at rest
- Weight goals are easier to plan when BMR is viewed together with body metrics
For a fuller picture, you may also compare your result with our BMI Calculator, Body Fat Calculator, and Ideal Weight Calculator.
Important Disclaimer
This BMR Calculator is designed for general health education and calorie planning. It does not diagnose medical conditions, and it should not be used as a substitute for medical, nutrition, or fitness advice tailored to your specific needs.
Estimate Only
Your BMR result is a formula-based estimate, not an exact lab measurement.
Not Medical Advice
If you have health concerns, eating disorders, metabolic conditions, or special nutrition needs, speak with a qualified healthcare professional.
Daily Needs Are Usually Higher
Your full calorie needs often exceed BMR because real life includes activity, digestion, movement, and exercise.
Why This Calculator Is Reliable
This BMR Calculator uses the Mifflin-St Jeor equation, a widely used formula for estimating resting energy needs. It is built to give a simple, practical estimate for wellness education and calorie planning.
This page is designed to help you understand:
- What BMR means in plain language
- How to calculate BMR using a widely accepted formula
- Why BMR is different from TDEE
- How age, sex, height, weight, and body composition can influence resting calorie needs
It is intended for educational and planning use only. Results are estimates and should be interpreted responsibly.
Frequently Asked Questions
BMR stands for basal metabolic rate. It is the estimated number of calories your body needs at rest to support essential functions such as breathing, circulation, and temperature control.
This page uses the Mifflin-St Jeor equation. The formula uses sex, age, height, and weight to estimate calories burned at rest each day.
There is no single “good” BMR for everyone. A normal result depends on your age, sex, height, weight, and body composition. BMR is best used as a personal estimate, not a score to compare competitively with others.
No. BMR covers calories burned at rest. TDEE includes BMR plus activity, exercise, digestion, and daily movement.
BMR varies because people differ in age, sex, height, weight, and body composition. Even two people with similar measurements may have different real-world energy needs.
Yes. BMR often changes with age. One reason is that body composition and lean mass may shift over time, which can influence resting energy expenditure.
Yes. More lean mass is often linked with higher energy expenditure at rest. That is one reason body composition matters when interpreting BMR.
BMR calculators are useful estimation tools, but they are not exact medical measurements. Real calorie needs can vary based on factors the formula does not fully capture.
That depends on your overall health, goals, and professional guidance. Because BMR reflects baseline energy needs, aggressive dieting around or below that level may not be appropriate for everyone. For more tailored guidance, speak with a qualified healthcare or nutrition professional.
Different formulas exist, but the Mifflin-St Jeor equation is commonly used for estimation in general adult populations. That is why it is used on this page.
Build a Smarter Wellness Plan with More Health Tools
Your BMR is a helpful starting point for calorie planning, but it is only one part of the bigger picture. Explore more body metrics, nutrition, and daily wellness calculators to better understand your health goals.
Browse Health Calculators