BMR Calculator
Calculate your Basal Metabolic Rate (BMR) using Mifflin-St Jeor and Revised Harris-Benedict clinical formulas.
Discover the precise baseline calories your body burns every day just staying alive at rest.
Enter Body Parameters
Mifflin-St Jeor Baseline
Recommended clinical resting expenditure benchmark.
Understanding Basal Metabolism
Basal Metabolic Rate (BMR) measures the minimum amount of energy your body burns to maintain life while at complete rest in a neutral environment.
Clinical Equations Used
Calculated using primary peer-reviewed metabolic predictive equations:
TDEE Multiplier Overview
| Activity Level | Multiplier | Description |
|---|---|---|
| Sedentary | 1.2x | Little or no exercise |
| Lightly Active | 1.375x | 1–3 workouts / week |
| Moderately Active | 1.55x | 3–5 workouts / week |
| Very Active | 1.725x | 6–7 heavy workouts / week |
Key Metabolic Concepts
- Organs consume most energy: Your brain, liver, heart, and kidneys account for over 60% of total baseline BMR.
- Lean mass boosts BMR: Muscle tissue burns significantly more calories at rest than fat tissue.
- Age impact: Metabolic rate gradually declines by ~1–2% per decade after age 30.
Frequently Asked Questions
What is Basal Metabolic Rate (BMR)?
BMR is the base amount of energy your body burns per 24 hours at rest to support essential functions such as breathing, heart rate, and cell repair.
Should I eat below my BMR to lose weight?
Consistently eating below your BMR is generally not recommended, as it can cause metabolic adaptation, muscle breakdown, and hormonal fatigue.
What is the difference between Mifflin-St Jeor and Harris-Benedict?
Mifflin-St Jeor was validated in 1990 and is proven more accurate for modern populations, whereas Harris-Benedict (revised 1984) slightly overestimates BMR in some individuals.