BMR Calculator - Basal Metabolic Rate
Free BMR calculator. Calculate your Basal Metabolic Rate (calories burned at rest) based on age, gender, weight, and height using the Mifflin-St Jeor equation.
Our free BMR calculator estimates your Basal Metabolic Rate — the number of calories your body burns at complete rest to maintain basic life functions like breathing, circulation, and cell production. This is the minimum energy your body needs to survive.
What is BMR?
BMR (Basal Metabolic Rate) represents the calories your body burns while at rest. It accounts for approximately 60-75% of your total daily calorie expenditure. Your BMR is determined by factors like age, gender, weight, and height.
Unlike TDEE (Total Daily Energy Expenditure), which includes activity, BMR focuses solely on your body's resting energy needs. Think of it as the calories you'd burn if you stayed in bed all day.
BMR vs TDEE
| Metric | What it measures | Usage |
|---|---|---|
| BMR | Calories burned at complete rest | Understanding minimum caloric needs |
| TDEE | Total calories burned per day including activity | Planning daily calorie intake for weight goals |
Mifflin-St Jeor Equation
Our calculator uses the Mifflin-St Jeor equation, the most accurate formula for estimating BMR in most adults:
For men: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5
For women: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161
Factors that affect BMR
- Age: BMR typically decreases by 2-3% per decade after age 20
- Gender: Men generally have higher BMR due to greater muscle mass
- Weight: Heavier individuals burn more calories at rest
- Height: Taller people have higher BMR due to greater surface area
- Body composition: Muscle burns more calories than fat
- Hormones: Thyroid hormones significantly impact metabolic rate
How to use your BMR
To estimate your total daily calorie needs, multiply your BMR by an activity factor:
- Sedentary (×1.2): Little to no exercise
- Lightly active (×1.375): Light exercise 1-3 days/week
- Moderately active (×1.55): Moderate exercise 3-5 days/week
- Very active (×1.725): Hard exercise 6-7 days/week
- Super active (×1.9): Physical job or training twice daily
Important notes
BMR calculations are estimates based on population averages. Individual metabolic rates vary due to genetics, hormones, muscle mass, and other factors. Use this calculator as a starting point and adjust based on your actual results. Consult a healthcare professional for personalized dietary advice.