BMR Calculator
Calculate your Basal Metabolic Rate (BMR) to estimate how many calories your body needs at rest based on age, gender, weight, and height.
※ Use if necessary
BMR Calculator
Calculate your Basal Metabolic Rate (BMR) to estimate how many calories your body burns at complete rest.
These results are for reference only and were developed for educational and testing purposes. You can also directly access and review the source code, including the logic and free APIs used on this page.
BMR Results
Daily Calorie Needs Based on Activity Level
| Activity Level | Description | Calories/Day |
|---|
BMR Calculator Guide
The Basal Metabolic Rate (BMR) Calculator estimates how many calories your body needs to maintain basic physiological functions at complete rest. This guide provides instructions on using the calculator and objective information about metabolic rate.
How to Use the BMR Calculator
Follow these steps to calculate your BMR:
- Enter Your Age: Input your current age in years (15-120).
- Select Your Gender: Choose male or female as biological sex affects BMR.
- Enter Your Height: Input your height in centimeters, inches, or feet.
- Enter Your Weight: Input your weight in kilograms or pounds.
- Select Formula: Choose between different BMR calculation methods.
- Calculate: Click "Calculate BMR" to view your results.
Understanding BMR
BMR represents the minimum number of calories your body needs to maintain basic functions like breathing, circulation, and cell production while at complete rest.
BMR Formulas
Different formulas for calculating BMR:
- Mifflin-St Jeor Equation (Most Accurate):
- Men: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age(y) + 5
- Women: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age(y) - 161
- Original Harris-Benedict Equation:
- Men: BMR = 66.5 + (13.75 × weight(kg)) + (5.003 × height(cm)) - (6.755 × age)
- Women: BMR = 655.1 + (9.563 × weight(kg)) + (1.850 × height(cm)) - (4.676 × age)
- Revised Harris-Benedict Equation:
- Men: BMR = 88.362 + (13.397 × weight(kg)) + (4.799 × height(cm)) - (5.677 × age)
- Women: BMR = 447.593 + (9.247 × weight(kg)) + (3.098 × height(cm)) - (4.330 × age)
- Katch-McArdle Formula (Requires Body Fat %):
- BMR = 370 + (21.6 × Lean Body Mass(kg))
- Lean Body Mass = Weight × (100 - Body Fat %) / 100
Factors Affecting BMR
Several factors influence your basal metabolic rate:
Body Composition
- Muscle tissue burns more calories at rest than fat tissue
- Higher muscle mass increases BMR
Age
- BMR typically decreases with age (about 1-2% per decade after 20)
- Due to loss of muscle mass and hormonal changes
Gender
- Men generally have higher BMR than women of same weight
- Due to typically higher muscle mass and lower body fat
Other Factors
- Genetics: Some people naturally have faster/slower metabolism
- Hormones: Thyroid hormones significantly influence BMR
- Pregnancy increases BMR
- Environmental temperature affects energy expenditure
Activity Level Multipliers
To estimate total daily energy expenditure (TDEE), multiply BMR by activity factor:
Sedentary (Little or No Exercise)
- BMR × 1.2
- Office job with little to no exercise
Lightly Active (Light Exercise 1-3 Days/Week)
- BMR × 1.375
- Light exercise or sports 1-3 days/week
Moderately Active (Moderate Exercise 3-5 Days/Week)
- BMR × 1.55
- Moderate exercise or sports 3-5 days/week
Very Active (Hard Exercise 6-7 Days/Week)
- BMR × 1.725
- Hard exercise or sports 6-7 days/week
Extra Active (Very Hard Exercise & Physical Job)
- BMR × 1.9
- Very hard exercise/sports and physical job
Using BMR for Weight Management
Understanding your BMR can help with weight goals:
Weight Loss
- Create calorie deficit below your TDEE
- Safe deficit: 500-1000 kcal/day (1-2 lb/week loss)
Weight Gain
- Create calorie surplus above your TDEE
- 300-500 kcal/day surplus for lean muscle gain
Weight Maintenance
- Match calorie intake to your TDEE
- Adjust as activity levels change
Final Tips for Using the Calculator
- Measure height and weight accurately for best results.
- Use the Mifflin-St Jeor formula for most accurate estimate.
- Be honest about your activity level when calculating TDEE.
- Re-calculate periodically as weight or activity changes.
This calculator provides estimates based on standard formulas. Individual metabolic rates may vary by up to 15% from these calculations.