BMR Calculator
Calculate your Basal Metabolic Rate (BMR).
How the BMR Calculator Works
Basal Metabolic Rate (BMR) represents the absolute minimum amount of energy (in calories) your body requires to stay alive and function at rest. This includes fundamental processes like breathing, maintaining body temperature, circulating blood, and cellular growth.
Understanding Your Results
- Resting Energy Only: Your BMR does not include the calories you burn by walking, exercising, or even digesting food.
- Starting Point: BMR is the foundational number used to calculate your Total Daily Energy Expenditure (TDEE).
Example Calculation
Consider a 30-year-old male who is 180 cm tall and weighs 80 kg. Using the widely respected Mifflin-St Jeor equation:
- Weight factor: 10 × 80 kg = 800
- Height factor: 6.25 × 180 cm = 1,125
- Age factor: 5 × 30 years = 150
- Sex constant: +5 for males
- Result: (800 + 1,125) - 150 + 5 = 1,780 kcal
This individual burns 1,780 calories if they stayed in bed all day without moving.
Common Mistakes to Avoid
Confusing BMR with TDEE
Do not eat exactly your BMR to maintain weight; you must eat your TDEE (BMR + activity). If you eat only your BMR, you will lose weight, as daily activity burns extra calories.
Ignoring Body Composition
Formulas use total weight. Because muscle burns more calories at rest than fat, highly muscular individuals may have a higher actual BMR than the formula estimates.
This calculator provides estimates for informational purposes only. Please read our Medical Disclaimer.
Real-World Examples
Basal Metabolic Rate of a 30-Year-Old Female
Inputs (The Math)
- GenderFemale
- Age30
- Height5 ft 4 in (162 cm)
- Weight140 lbs (63.5 kg)
Outputs (The Result)
- BMR1,373 Calories/day
Why it works this way
This individual requires 1,373 calories per day just to keep her body alive at rest. She should never eat below this number, as it can cause metabolic damage and muscle loss.
- Calculated using the Mifflin-St Jeor equation.
- Assumes normal body composition.
BMI vs. BMR: Which Should You Use?
Understand the difference between Body Mass Index and Basal Metabolic Rate.
| Feature | BMI Calculator | BMR Calculator |
|---|---|---|
| Primary Purpose | Assesses weight categories (underweight, normal, overweight, obese) | Estimates baseline daily calorie burn at rest |
| Required Inputs | Height, Weight | Height, Weight, Age, Gender |
| Limitations | Does not account for muscle mass vs. fat | Only estimates resting calories, not total daily expenditure (TDEE) |
Frequently Asked Questions
What is BMR?
BMR is the number of calories your body needs to accomplish its most basic life-sustaining functions (like breathing, blood circulation, and cellular growth).
How does age affect BMR?
As you age, your BMR typically decreases because muscle mass tends to decline, slowing down your metabolism.
Medical Disclaimer
This calculator is for informational purposes only. Do not use this information to diagnose or treat a health problem without consulting a qualified healthcare provider.
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