BMR Calculator
Estimate your Basal Metabolic Rate from your age, sex, height and weight using the Mifflin-St Jeor equation.
Calculate Your BMR
Enter your basic information to estimate the calories your body uses at rest.
Estimated Daily Calorie Needs
| Activity Level | Multiplier | Approx. Calories |
|---|---|---|
| Sedentary | 1.20 | — |
| Lightly Active | 1.375 | — |
| Moderately Active | 1.55 | — |
| Very Active | 1.725 | — |
| Extra Active | 1.90 | — |
What Is BMR?
Basal Metabolic Rate, or BMR, is an estimate of the amount of energy your body needs to maintain essential functions while at rest. These functions include processes such as breathing, circulation and maintaining body temperature.
BMR is not the same as the total number of calories you burn during a normal day. Everyday movement, exercise, digestion and other activities increase total energy expenditure above your estimated BMR.
How to Use the BMR Calculator
- Select your sex.
- Enter your age in years.
- Choose metric or imperial measurements.
- Enter your height and weight.
- Click Calculate BMR.
- Review your estimated BMR and the optional activity-based calorie estimates.
BMR Formula
This calculator uses the Mifflin-St Jeor equation, a commonly used estimation equation for resting energy requirements in adults.
BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
For females:
BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
When imperial units are selected, the calculator first converts the entered measurements to metric units before applying the equation.
BMR Example
Male, age 30, weight 70 kg, height 175 cm
BMR = (10 × 70) + (6.25 × 175) − (5 × 30) + 5
BMR = 700 + 1093.75 − 150 + 5
BMR ≈ 1,648.75 calories per day
The result is an estimate of the energy required to support basic bodily functions at rest. It is not a prediction of the person's actual total daily calorie expenditure.
BMR vs. TDEE
BMR
Estimates the energy needed to support essential functions while the body is at rest.
Activity
Movement, exercise and daily activities increase the amount of energy used throughout the day.
TDEE
Total Daily Energy Expenditure is an estimate that incorporates BMR and energy used through activity and other processes.
Understanding the Activity Estimates
The calculator also applies commonly used activity multipliers to the estimated BMR. These values provide a rough estimate of daily energy needs and should not be treated as exact calorie requirements.
- Sedentary: little or no regular exercise.
- Lightly active: light exercise or activity several days per week.
- Moderately active: moderate exercise or activity on a regular basis.
- Very active: frequent intense exercise or physically demanding activity.
- Extra active: very demanding physical activity or intensive training.
Practical Uses of a BMR Calculator
A BMR estimate can be useful as a starting point when learning about energy expenditure and planning a broader nutrition or fitness strategy.
Understanding Resting Energy Needs
BMR provides a simple estimate of how much energy the body requires for basic functions when resting.
Comparing Energy Estimates
Combining an estimated BMR with an activity multiplier can provide a rough estimate of daily calorie requirements.
Fitness Planning
People may use BMR as one input when learning about calorie balance, exercise and nutrition planning.
Common BMR Calculation Mistakes
- Confusing BMR with total daily calorie expenditure.
- Entering pounds where kilograms are expected.
- Entering height in inches or feet when using the metric fields.
- Treating an estimated BMR as an exact measurement.
- Assuming the same calorie requirement applies every day regardless of activity or circumstances.
Important Limitations
The result is calculated from age, sex, height and weight using an estimation equation. Individual energy requirements can differ because of body composition, activity, genetics, health status and other factors.
This calculator is provided for general informational and educational purposes. It should not be used as a substitute for individualized medical or dietary advice. If you have specific health, nutrition or weight-related concerns, consult an appropriately qualified healthcare professional.
Frequently Asked Questions
What does BMR stand for?
BMR stands for Basal Metabolic Rate. It is an estimate of the energy your body needs to support essential functions while at rest.
How is BMR calculated?
This calculator uses the Mifflin-St Jeor equation, which uses age, sex, height and weight to estimate BMR.
Is BMR the same as daily calorie needs?
No. BMR represents resting energy needs. Total daily energy expenditure also includes physical activity, exercise, digestion and other energy demands.
What is a good BMR?
There is no single ideal BMR value. BMR varies naturally according to factors such as body size, age, sex and body composition.
Can I use BMR for weight loss planning?
BMR can be one input when estimating overall energy needs, but it should not be treated as an exact calorie target. Individual circumstances can significantly affect actual energy requirements.
Why does BMR change with age and weight?
The equation incorporates age and body weight because these factors are associated with differences in estimated resting energy requirements.
Is the BMR result exact?
No. BMR calculators provide estimates based on mathematical equations. Actual resting energy expenditure can differ from the calculated value.
Related Tools
Calculate Your BMR
Enter your information above to estimate your Basal Metabolic Rate and explore approximate activity-based daily calorie needs.
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