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.
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. It represents the minimum amount of energy your body needs to survive when you're completely at rest.
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. Understanding your BMR is essential for creating effective nutrition and weight management plans.
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. By knowing your BMR and TDEE, you can determine how many calories you need to consume to maintain, lose, or gain weight.
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. It's calculated by multiplying your BMR by an activity factor that represents your level of physical activity.
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, you need to consume fewer calories than your TDEE (calorie deficit). To gain weight, you need to consume more calories than your TDEE (calorie surplus). To maintain weight, you should consume calories equal to your TDEE.
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 (pounds and inches) to metric units (kilograms and centimeters) 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. Simply select your unit system, enter your details, choose your activity level, and get your BMR and TDEE along with calorie recommendations for weight management.
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. You're active but not consistently.
Moderately Active (Multiplier: 1.55)
Moderate exercise 3-5 days per week. This includes regular workouts, moderate-intensity cardio, or strength training. Most active individuals fall into this category.
Very Active (Multiplier: 1.725)
Hard exercise 6-7 days per week. This includes intense workouts, high-intensity training, or physically demanding activities. Athletes and very active individuals typically fall into this category.
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 who also exercise regularly.
Tip: If you're unsure which activity level to choose, start with a lower level and adjust based on your results. It's better to underestimate than overestimate your activity level for weight loss goals.
Common Use Cases
- Weight Loss Planning: Calculate your TDEE and create a calorie deficit by consuming 300-500 fewer calories per day for safe, sustainable weight loss
- Weight Gain Planning: Calculate your TDEE and create a calorie surplus by consuming 300-500 more calories per day for healthy weight gain
- Weight Maintenance: Determine your TDEE to maintain your current weight by matching your calorie intake to your energy expenditure
- 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, lose fat, or change your activity levels
- Meal Prep: Calculate daily and weekly calorie needs to plan and prepare meals that align with your goals
- Medical Nutrition Therapy: Healthcare providers use BMR calculations to develop personalized nutrition plans for patients
- 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 = 1,441 calories/day
TDEE Calculation: 1,441 × 1.55 = 2,234 calories/day
Weight Loss Goal: 2,234 - 500 = 1,734 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 = 1,780 calories/day
TDEE Calculation: 1,780 × 1.375 = 2,448 calories/day
Maintenance Goal: Consume approximately 2,448 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 = 1,644 calories/day
TDEE Calculation: 1,644 × 1.725 = 2,836 calories/day
Weight Gain Goal: 2,836 + 500 = 3,336 calories/day (aim for ~1 lb/week weight gain)
Frequently Asked Questions
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest, just to maintain basic life functions. TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor, representing the total calories you burn in a day including all activities. TDEE is what you should use for weight management planning.
This calculator uses the Mifflin-St Jeor Equation, which is currently considered the most accurate BMR formula. It was developed in 1990 and has been validated against direct calorimetry measurements. It's more accurate than older formulas like the Harris-Benedict Equation.
The Mifflin-St Jeor Equation is accurate within about 10% for most people. However, individual variations in metabolism, body composition, and other factors mean that your actual BMR may differ. Use the calculated BMR as a starting point and adjust based on your results. If you're not seeing expected weight changes after 2-3 weeks, adjust your calorie intake accordingly.
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. Remember that most people overestimate their activity level. If you're trying to lose weight and not seeing results, you may need to select a lower activity level or reduce your calorie intake further.
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. A larger deficit (500-1000 calories) may be appropriate for some people, but consult with a healthcare provider before creating a larger deficit. Never go below your BMR, as this can slow your metabolism and cause health issues.
For healthy weight gain, aim for a calorie surplus of 300-500 calories per day above your TDEE. This typically results in about 0.5-1 pound of weight gain per week. Focus on nutrient-dense foods and combine increased calories with strength training to build muscle rather than just fat. Consult with a healthcare provider or nutritionist for personalized guidance.
Yes, your BMR changes with age (decreases about 1-2% per decade after age 30), body composition (more muscle increases BMR), weight changes, and other factors. As you lose weight, your BMR decreases because you have less body mass to maintain. As you gain muscle, your BMR increases because muscle tissue burns more calories at rest than fat tissue. Recalculate your BMR periodically, especially after significant weight changes.
No. All calculations are performed locally in your browser. We don't store, save, or transmit any personal information or measurements. Your privacy is protected.