BMR Calculator: Determine Your Daily Caloric Needs Easily
Calculate your Basal Metabolic Rate (BMR) - the calories your body burns at rest. This calculator helps determine your daily energy needs based on age, gender, height, and weight, using scientifically validated formulas.
Personal Information
Body Measurements
Select Formula
Your Basal Metabolic Rate (BMR):
| Activity Level | Calories |
|---|---|
|
Sedentary (little or no exercise)
|
0 |
|
Light Exercise (1-3 times/week)
|
0 |
|
Moderate Exercise (4-5 times/week)
|
0 |
|
Daily Exercise/Active
|
0 |
|
Very Active (intense exercise 6-7x/week)
|
0 |
|
Extra Active (very intense daily exercise/physical job)
|
0 |
Activity Level Details
- Exercise: 15-30 minutes of elevated heart rate activity
- Intense exercise: 45-120 minutes of elevated heart rate activity
- Very intense exercise: 2+ hours of elevated heart rate activity
BMR Calculation Formulas
Calculation Formulas:
Mifflin-St Jeor:
Women: BMR = 10W + 6.25H - 5A - 161
Harris-Benedict:
Women: BMR = 9.247W + 3.098H - 4.330A + 447.593
Katch-McArdle:
Where:
- W = weight in kg
- H = height in cm
- A = age
- F = body fat in decimal form
Energy Distribution:
Factors Affecting BMR
Muscle Mass
Having more muscle mass increases your BMR significantly as muscle tissue requires more energy to maintain than fat tissue. Weight training can help increase muscle mass and boost BMR.
Age
BMR typically decreases with age due to reduced muscle mass and slower metabolic processes. The decrease is approximately 1-2% per decade after age 20.
Gender
Men generally have higher BMRs than women due to greater muscle mass, organ size, and hormonal differences that affect body composition.
Body Temperature
Every increase of 0.5°C in core body temperature increases BMR by about 7%. This is why fever or exposure to extreme temperatures can affect your metabolic rate.
Hormonal Factors
Thyroid hormones, growth hormone, and stress hormones all influence BMR. Conditions affecting these hormones can significantly impact metabolic rate.
Diet and Nutrition
Regular eating patterns maintain BMR, while severe calorie restriction can lower it. Certain foods and supplements may temporarily boost metabolic rate.
Sleep and Recovery
Poor sleep quality or insufficient sleep can lower BMR by affecting hormone production and regulation. Aim for 7-9 hours of quality sleep.
Health Status
Various medical conditions and medications can affect BMR. Chronic diseases, infections, and healing processes often increase metabolic rate.
Genetics
Genetic factors can influence your base metabolic rate by affecting muscle mass potential, hormone levels, and how efficiently your body uses energy.
Frequently Asked Questions
- Set realistic weight loss/gain goals
- Create an effective meal plan
- Avoid under-eating, which can slow metabolism
- Make informed decisions about your daily calorie needs
- Higher percentage of muscle mass
- Lower body fat percentage
- Larger organs that require more energy
- Hormonal differences, particularly testosterone levels
- Natural loss of muscle mass (1-2% per year after age 30)
- Hormonal changes
- Reduced organ function and cellular activity
- Changes in body composition
However, regular exercise, particularly strength training, can help maintain a higher BMR as you age.
- Building muscle through resistance training
- Maintaining consistent eating patterns
- Getting adequate sleep (7-9 hours)
- Staying hydrated
- Managing stress levels
Note that crash diets can lower your BMR by triggering the body's starvation response.
- Every 10-15 pounds of weight change
- After significant muscle gain or loss
- Every 6-12 months as you age
- During major life changes (pregnancy, menopause, etc.)
Medical Disclaimer
This calculator provides estimates only. Consult a healthcare provider before making any dietary or exercise changes.