BMR Calculator
Calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE). Determine how many calories your body burns at rest and with activity. Perfect for weight management and nutrition planning.
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Table of Contents
What is BMR?
**Basal Metabolic Rate (BMR)** is the number of calories your body burns at rest to maintain basic physiological functions such as breathing, circulation, cell production, brain function, and maintaining body temperature.
BMR accounts for approximately 60-75% of your total daily calorie expenditure. It's influenced by several factors including age, gender, weight, height, and body composition.
Your BMR is the foundation for calculating your Total Daily Energy Expenditure (TDEE), which includes all the calories you burn through physical activity and daily movement.
What is TDEE?
**Total Daily Energy Expenditure (TDEE)** is the total number of calories your body burns in a day, including all activities from basic metabolic functions to exercise.
TDEE = BMR × Activity Multiplier
The activity multiplier accounts for:
- Basal Metabolic Rate (BMR) - Calories burned at rest (60-75% of TDEE)
- Non-Exercise Activity Thermogenesis (NEAT) - Daily activities like walking, fidgeting (15-20% of TDEE)
- Exercise Activity Thermogenesis (EAT) - Structured exercise and workouts (5-10% of TDEE)
- Thermic Effect of Food (TEF) - Energy used to digest food (10% of TDEE)
Knowing your TDEE is crucial for weight management. To lose weight, consume fewer calories than your TDEE. To gain weight, consume more. To maintain weight, consume equal calories.
How it Works
This calculator uses the **Mifflin-St Jeor Equation**, which is currently considered the most accurate formula for estimating BMR. The equation was developed in 1990 and has been validated against direct calorimetry measurements.
Mifflin-St Jeor Equation
The formula differs slightly for men and women:
Men: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age(years) + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age(years) - 161
The calculator automatically converts imperial units to metric for the calculation, then displays results in calories per day.
TDEE Calculation
Once BMR is calculated, TDEE is determined by multiplying BMR by an activity multiplier:
The activity multiplier ranges from 1.2 (sedentary) to 1.9 (extremely active) based on your selected activity level.
Our calculator automatically handles all conversions and calculations, giving you instant results as you enter your information.
Activity Levels
Selecting the correct activity level is crucial for accurate TDEE calculation. Here's what each level means:
Sedentary (Multiplier: 1.2)
Little or no exercise, desk job, minimal daily movement. Most people who work office jobs and don't exercise regularly fall into this category.
Lightly Active (Multiplier: 1.375)
Light exercise 1-3 days per week. This includes activities like walking, light jogging, or light resistance training.
Moderately Active (Multiplier: 1.55)
Moderate exercise 3-5 days per week. This includes regular workouts, moderate-intensity cardio, or strength training.
Very Active (Multiplier: 1.725)
Hard exercise 6-7 days per week. This includes intense workouts, high-intensity training, or physically demanding activities.
Extremely Active (Multiplier: 1.9)
Physical job or hard exercise 2x per day. This includes professional athletes, construction workers, or individuals with very physically demanding jobs.
Tip: If you're unsure which activity level to choose, start with a lower level and adjust based on your results.
Common Use Cases
- Weight Loss Planning: Calculate your TDEE and create a calorie deficit of 300-500 fewer calories per day
- Weight Gain Planning: Calculate your TDEE and create a calorie surplus of 300-500 more calories per day
- Weight Maintenance: Determine your TDEE to maintain your current weight
- Nutrition Planning: Use BMR and TDEE to plan meal timing, macronutrient distribution, and daily calorie targets
- Fitness Tracking: Monitor changes in your BMR and TDEE as you build muscle or change your activity levels
- Meal Prep: Calculate daily and weekly calorie needs to plan and prepare meals
- Medical Nutrition Therapy: Healthcare providers use BMR calculations to develop personalized nutrition plans
- Athletic Performance: Athletes use TDEE to ensure they're consuming enough calories to fuel performance and recovery
Examples
Example 1: Weight Loss
Person: 30-year-old female, 70 kg, 165 cm, Moderately Active
BMR Calculation: 10 × 70 + 6.25 × 165 - 5 × 30 - 161 = 1,420 calories/day
TDEE Calculation: 1,420 × 1.55 = 2,201 calories/day
Weight Loss Goal: 2,201 - 500 = 1,701 calories/day (aim for ~1 lb/week weight loss)
Example 2: Weight Maintenance
Person: 35-year-old male, 80 kg, 180 cm, Lightly Active
BMR Calculation: 10 × 80 + 6.25 × 180 - 5 × 35 + 5 = 1,755 calories/day
TDEE Calculation: 1,755 × 1.375 = 2,413 calories/day
Maintenance Goal: Consume approximately 2,413 calories/day to maintain current weight
Example 3: Weight Gain
Person: 25-year-old male, 65 kg, 175 cm, Very Active
BMR Calculation: 10 × 65 + 6.25 × 175 - 5 × 25 + 5 = 1,624 calories/day
TDEE Calculation: 1,624 × 1.725 = 2,801 calories/day
Weight Gain Goal: 2,801 + 500 = 3,301 calories/day (aim for ~1 lb/week weight gain)
Frequently Asked Questions
BMR is the number of calories your body burns at complete rest. TDEE is your BMR multiplied by an activity factor, representing the total calories you burn in a day including all activities.
This calculator uses the Mifflin-St Jeor Equation, which is currently considered the most accurate BMR formula. It was developed in 1990 and is more accurate than older formulas like the Harris-Benedict Equation.
The Mifflin-St Jeor Equation is accurate within about 10% for most people. Use the calculated BMR as a starting point and adjust based on your results.
Be honest about your activity level. Consider both structured exercise and daily activities. If you're unsure, start with a lower activity level and adjust based on your results.
For safe, sustainable weight loss, aim for a calorie deficit of 300-500 calories per day below your TDEE. This typically results in about 0.5-1 pound of weight loss per week. Never go below your BMR.
For healthy weight gain, aim for a calorie surplus of 300-500 calories per day above your TDEE. Focus on nutrient-dense foods and combine with strength training.
Yes, your BMR changes with age, body composition, and weight changes. As you lose weight, your BMR decreases. As you gain muscle, your BMR increases. Recalculate periodically.
No. All calculations are performed locally in your browser. We don't store, save, or transmit any personal information or measurements.